Expenses Guided Notes Unit 3 • Business Math • Topic 1: Expenses & Expenditures Slides 1–3
Understanding Your Expenses
Name: Date:
Essential Vocabulary
Slide 2
• Budget: A financial plan that helps you track your income and allocate it toward saving and spending.
• Expense / Expenditure: Any money that you spend or pay out to cover costs.
Types of Expenditures
Slide 2
Fixed Expenses:
Costs that remain constant every month.
Examples: rent, auto loans, subscription services.
Variable Expenses:
Costs that change from month to month.
Examples: utility bills, gas, or groceries.
Calculating Averages
Slide 2
To project future costs and budget accurately, we calculate the average spending over a specific timeframe.
Average Monthly Expense = Total Expenditures ÷ Number of Months
Example Walkthrough: The Hurt Family (5 Months: $2,786, $3,001, $2,875, $2,663, and $2,803)
• Step 1 (Sum): $2,786 + $3,001 + $2,875 + $2,663 + $2,803 = $14,128
• Step 2 (Divide): $14,128 ÷ 5 = $2,825.60 / mo
I DO: Calculating Average Monthly Expenditure
Slide 3
Scenario 2: The Quick family track their CenterPoint energy bills from January through September: $224.58, $238.91, $201.76, $170.59, $173.38, $199.04, $202.63, $205.19, and $193.22.
Step 1: Total Expenditures (Sum 9 Months)
Total Sum = $
Step 2: Average Monthly (Divide by 9)
Average = $ / mo
Unit 3 • Topic 1: Expenses & Expenditures Guided Notes Page 1 of 4
Unit 3 • Business Math • Topic 1: Expenses & Expenditures Slides 4–5
Averaging Practice: WE DO & YOU DO
WE DO: Calculating Average Monthly Expenditure
Slide 4
Scenario 3: The Johnson family track their water bills from January through August: $61.33, $58.05, $55.93, $57.72, $60.95, $68.28, $71.67, and $63.44. What is their average monthly expenditure so far this year?
Step 1: Total Expenditures (Sum 8 Months)
Write sum here:
Total Sum = $
Step 2: Average Monthly (Divide by 8)
Write division here:
Average = $ / mo
YOU DO: Practice Calculating Average Monthly Expenditure
Slide 5
Task 1: Average Expenditure (Johnson Family 4 Months)
The Johnson family’s total expenditures for the past four months were $2,582.48, $3,132.59, $2,603.88, and $2,748.37. What is their average monthly expenditure?
Step 1: Find Total Expenditures (Sum 4)
Total Sum = $
Step 2: Calculate Average (Divide by 4)
Average = $ / mo
Task 2: Average Expenditure (Tommy Thompson Gas)
Over the past five months, Tommy Thompson has kept track of how much he’s spent on gas: $94.29, $98.80, $127.63, $102.53, and $139.71. What was his average gas expense?
Step 1: Find Total Expenditures (Sum 5)
Total Sum = $
Step 2: Calculate Average (Divide by 5)
Average = $ / mo
Unit 3 • Topic 1: Expenses & Expenditures Guided Notes Page 2 of 4
Unit 3 • Business Math • Topic 1: Expenses & Expenditures Slides 6, 7 & 10
Working Backward from an Average
Concept & Strategy: Working Backward
Slides 6 & 7
Sometimes you know the target average and want to find a missing month's limit. To solve this, work backward using the total target budget for the period.
Target Total = Target Average × Total Months
1 Target Total
Find total budget needed for period.
2 Known Sum
Add expenditures already recorded.
3 Subtract
Subtract known sum from target to find limit.
I DO: Byrley Groceries Slide 6
Q1 Avg: $357.85. April: $383.79, May: $341.44. June limit?
Step 1: $357.85 × 3 = $
Step 2: $383.79 + $341.44 = $
Step 3: June Limit = $
WE DO: Wayne Groceries Slide 7
Q2 Avg: $483.26. July: $528.37, August: $463.92. Sept limit?
Step 1: $483.26 × 3 = $
Step 2: $528.37 + $463.92 = $
Step 3: Sept Limit = $
Common Pitfalls: Working Backward from an Average
Slide 10
Pitfall 1: Wrong Month Multiplier
Students multiply by only recorded months instead of the entire period.
✓ Rule: Target Total = Average × Total Months
Pitfall 2: Including the Missing Month
Do not include a placeholder value or the average itself in the known sum.
✓ Rule: Known Sum = Only Add Completed Months
Unit 3 • Topic 1: Expenses & Expenditures Guided Notes Page 3 of 4
Unit 3 • Business Math • Topic 1: Expenses & Expenditures Slides 8 & 9
YOU DO: Practice Working Backward from an Average
Core Strategy Reminder: Target Total = Target Average × Total Months 1. Find Total Budget Needed • 2. Add Recorded Expenditures • 3. Target Total - Known Sum = Limit
Slide 9
Task 1: Dining Out Budget (Matthew Matthews)
Matthew Matthews’ average monthly expense for Dining Out for the first four months of the year was $137.85. In May, he spent $119.68, in June he spent $148.90, and in July he spent $154.83. How much can he spend in August to have the same average as the first four months?
Slide 8
1 Total Budget Needed
Target: $137.85 × 4 =
Target = $
2 Total Spent So Far
Sum: May + Jun + Jul =
Known = $
3 August Spending Limit
Target - Known =
Limit = $ / mo
Task 2: Grocery Budget (The Byrley Family Q2)
The Byrley family’s average monthly expense for groceries for the first quarter (Jan, Feb, Mar) was $357.85. In April they spent $383.79, and in May they spent $341.44. How much can they spend in June to maintain their 1st quarter average?
Slide 8 & 9
1 Total Q2 Budget Needed
Target: $357.85 × 3 =
Target = $
2 Total Spent So Far
Sum: April + May =
Known = $
3 June Spending Limit
Target - Known =
Limit = $ / mo
Unit 3 • Topic 1: Expenses & Expenditures Guided Notes Page 4 of 4
Expenditure Practice Worksheet Unit 3 • Business Math • Practice Set 1 Expenses & Expenditures
Expenditure Practice Worksheet
Name: Date:
Core Formula: Average Monthly Expense = Total Expenditures ÷ Number of Months
Part A: Calculating Average Monthly Expenditures (YOU DO Tasks)
Task 1: Johnson Family Total Expenditures 4-Month Period
The Johnson family’s total expenditures for the past four months were $2,582.48, $3,132.59, $2,603.88, and $2,748.37. What is their average monthly expenditure?
Step 1: Find Total Expenditures (Sum 4 Months)
Write addition equation:
Total Sum = $
Step 2: Calculate Average Monthly (Divide by 4)
Write division equation:
Average = $ / mo
Task 2: Tommy Thompson Gas Spending 5-Month Period
Over the past five months, Tommy Thompson has kept track of how much he’s spent on gas: $94.29, $98.80, $127.63, $102.53, and $139.71. What was the average amount he spent on gas?
Step 1: Find Total Expenditures (Sum 5 Months)
Write addition equation:
Total Sum = $
Step 2: Calculate Average Monthly (Divide by 5)
Write division equation:
Average = $ / mo
Concept Check: Label each as Fixed (F) or Variable (V)
[ ] Apartment Rent
[ ] Electric Utility Bill
[ ] Car Loan Payment
[ ] Grocery Shopping
Unit 3 • Business Math • Practice Worksheet Page 1 of 2
Unit 3 • Business Math • Practice Set 1 Expenses & Expenditures
Working Backward from an Average
Backwards Formula: Target Total = Target Average × Total Months | Limit = Target Total - Known Sum
Task 4: Matthew Matthews Dining Out Budget 4-Month Target Target
Matthew’s average monthly expense for Dining Out for the first four months of the year was $137.85. In May, he spent $119.68, in June he spent $148.90, and in July he spent $154.83. How much can he spend in August to maintain the same average as the first four months?
1 Total Budget Needed
Target: $137.85 × 4 =
Target = $
2 Total Spent So Far
Sum: May + Jun + Jul
Known = $
3 August Spending Limit
Target - Known =
Limit = $ / mo
Task 5: Byrley Family Grocery Budget (Q2 Balance) 3-Month Quarter
The Byrley family’s average monthly expense for groceries for the 1st quarter (Jan, Feb, Mar) was $357.85. In April they spent $383.79, and in May they spent $341.44. How much can they spend in June to maintain their 1st quarter average?
Expenses Learning Check Unit 3 • Business Math • Formative Assessment Score: ______ / 25 pts
Learning Check: Expenses & Expenditures
Show all calculation steps clearly. Write dollar signs and round to the nearest cent where necessary.
Name:
Date: Period:
1 Type 1: Finding an Average Monthly Expense
10 Points
The Hurt family’s records for the past five months show that their expenditures totaled $2,786, $3,001, $2,875, $2,663, and $2,803. What is their average monthly expenditure for the five months?
Step 1: Calculate the Total Expenditures (Sum 5 Months) [5 pts]
Sum: 2,786 + 3,001 + 2,875 + 2,663 + 2,803 =
Total Expenditures = $
Step 2: Calculate the Average Monthly Expense [5 pts]
Average: Total Expenditures ÷ 5 =
Average Monthly = $ / month
2 Type 2: Working Backward from an Average
15 Points
The Wayne family's average monthly grocery expense for Q2 was $483.26. In July they spent $528.37 and in August they spent $463.92. How much can they spend in September to maintain their Q2 average?
1 Total Q3 Budget Needed
Target: $483.26 × 3 =
Target = $
2 Total Spent So Far
Sum: $528.37 + $463.92 =
Known = $
3 Sept Spending Limit
Target - Known =
Limit = $ / mo
Concept Verification
Circle the correct answer:
When budgeting a quarter (3 months), multiply the average by:
[ A ] 2 months [ B ] 3 months [ C ] 4 months
Which expense type fluctuates based on usage and billing cycle?
[ A ] Fixed [ B ] Variable [ C ] Deductible
Unit 3 • Topic 1: Expenses & Expenditures Learning Check Total: 25 Points
Expenses Teacher Guide Unit 3 • Business Math • Teacher Facilitation Guide Answer Key & Lesson Plan
Topic 1: Expenses & Expenditures
Instructional pacing: 50–60 minutes • Calculators permitted
Target Level: Business Math / Personal Finance
Prerequisites: Multi-digit addition & decimal division
1. Hook & Vocab 10 Mins (Slides 1–2)
Define Budget, Expense, Fixed vs Variable.
2. Direct / Guided 15 Mins (Slides 3–5)
I DO / WE DO on multi-month averaging.
3. Backwards Budget 15 Mins (Slides 6–10)
Target total minus known sum method.
4. Formative Check 10 Mins (Slide 11)
Learning Check assessment.
Guided Notes Answer Key (Filled Blanks in Bold Teal)
Slide 2: Essential Vocabulary & Types
• Budget: A financial plan that helps you track your income and allocate it toward saving and spending.
• Expense / Expenditure: Any money that you spend or pay out to cover costs.
• Fixed Expenses: Costs that remain constant every month (Rent, loans).
• Variable Expenses: Costs that change from month to month (Utilities, groceries).
Slide 2 & 3: Calculating Averages
• Formula: Average Monthly Expense = Total Expenditures ÷ Number of Months
• Hurt Walkthrough: Step 1 = $14,128; Step 2 = $14,128 ÷ 5 = $2,825.60 / mo
• Quick Family (I DO, Slide 3):
Step 1 Sum: 224.58 + 238.91 + 201.76 + 170.59 + 173.38 + 199.04 + 202.63 + 205.19 + 193.22 = $1,809.30
Step 2 Average: $1,809.30 ÷ 9 = $201.03 / month (rounded)
Slide 4: WE DO Walkthrough (Johnson Family Water Bills)
Step 1 Sum (8 Months): 61.33 + 58.05 + 55.93 + 57.72 + 60.95 + 68.28 + 71.67 + 63.44 = $497.37
Step 2 Average: $497.37 ÷ 8 = $62.17 / month (rounded from $62.17125)
Teaching Tip: Rounding & Precision
Remind students that financial calculations always round to the hundredths place (cents) unless instructed otherwise. When dividing $1,809.30 by 9, the quotient is 201.0333..., so students must truncate/round cleanly to $201.03.
Unit 3 • Topic 1: Expenses & Expenditures Teacher Guide Page 1 of 2
Unit 3 • Business Math • Teacher Solutions Solutions Key
Practice Worksheet & Learning Check Solutions
Practice Worksheet Detailed Solutions
Task 1: Johnson Family 4-Month Expenditures
• Sum: $2,582.48 + $3,132.59 + $2,603.88 + $2,748.37 =
Budgeting Guided Notes Unit 3 • Business Math • Topic 2: Budgeting Principles Slides 12–13 & Strategies
Understanding Budgets & Their Importance
Name: Date:
What is a Budget?
Slide 12
A budget is a dynamic, written plan that estimates and details your expected income, planned expenses, and savings goals over a specific timeframe.
It acts as a financial road map, ensuring every dollar has a dedicated job before you spend it.
1. Income Tracking: Knowing exact net (take-home) pay.
2. Expenses & Needs: Allocating money to critical living costs.
3. Savings & Wants: Tucking away emergency funds and fun money.
Why is Budgeting Important?
Slide 12
Budgeting isn't about restricting choices; it gives you intentional control over your money.
✓ Prevents Deficits & Debt:
Keeps you from spending more than you earn, avoiding debt cycles.
✓ Builds Security:
Prioritizes "paying yourself first" for surprise emergencies.
✓ Achieves Long-Term Goals:
Actively save for milestones like cars, college, or housing.
Understanding Expenses: Needs vs. Wants & Fixed vs. Variable
Slide 13
Needs vs. Wants:
Needs: Essential for survival, basic health, and employment. Skipping leads to severe consequences.
Wants: Non-essential items that increase comfort or happiness but are not required to live or work.
• Needs: Rent, groceries, utility bills, health insurance, transit.
• Wants: Dining out, designer clothes, gaming, subscriptions.
Fixed vs. Variable Expenses:
Fixed: Costs that remain identical every single billing cycle. Predictable and easy to schedule.
Variable: Costs that fluctuate in price or frequency. Require tracking and averaging.
• Fixed: Rent/mortgage ($1,200), auto ins. ($120), gym ($30).
• Variable: Electric ($80–$160), groceries ($300–$450), gas ($90–$140).
Budgeting Strategies: 3 Ways to Save
Strategy Slide
The 50/30/20 Plan The Balanced Guide
Splits paycheck into three simple parts:
• 50% Needs: Rent, food, bills.
• 30% Wants: Fun, dining, hobbies.
• 20% Savings: Future buffer.
Zero-Based Plan The Precise System
Personal Budgeting Worksheet Unit 3 • Business Math • Practice Set 2 Budgeting Principles & Modeling
Personal Budgeting Worksheet
Name: Date:
Baseline Rules: Gross Monthly = Annual ÷ 12 | Tax = Gross × 0.25 | Net = Gross - Tax
Part 1: Career Income & Deductions Modeling
Profile A: Graphic Designer $48,000 / yr
1. Gross Monthly Income:
$48,000 ÷ 12 =
$
2. Estimated Taxes (25%):
Gross × 0.25 =
$
3. Net Monthly Income (Take-Home):
$
Profile B: Dental Hygienist $72,000 / yr
1. Gross Monthly Income:
$72,000 ÷ 12 =
$
2. Estimated Taxes (25%):
Gross × 0.25 =
$
3. Net Monthly Income (Take-Home):
$
Part 2: The 50/30/20 Plan Application (Graphic Designer Net Pay)
Apply the 50/30/20 budgeting rule to the Graphic Designer's Net Monthly Take-Home Pay from Part 1 ($3,000.00):
50% Needs Allocation
Rent, groceries, utilities, transit.
$3,000 × 0.50 =
$
30% Wants Allocation
Dining out, entertainment, hobbies.
$3,000 × 0.30 =
$
20% Savings Allocation
Emergency fund, long-term investments.
$3,000 × 0.20 =
$
Unit 3 • Business Math • Practice Worksheet Page 1 of 2
Unit 3 • Business Math • Practice Set 2 Budgeting Principles & Modeling
Itemized Budget Ranges & Strategy Analysis
Part 3: Itemized Spending Ranges (Dental Hygienist Net Pay: $4,500.00)
Calculate the exact dollar target ranges for the Dental Hygienist's monthly budget based on their Net Take-Home Pay of $4,500.00 :
1. Rent / Housing (25% – 28%)
$4,500 × 0.25 to $4,500 × 0.28
$ – $
2. Utilities & Bills (7% – 10%)
$4,500 × 0.07 to $4,500 × 0.10
$ – $
3. Food & Groceries (5% – 9%)
$4,500 × 0.05 to $4,500 × 0.09
$ – $
4. Car & Transit (10% – 12%)
$4,500 × 0.10 to $4,500 × 0.12
$ – $
Part 4: Budget Strategy Case Studies (Matching & Analysis)
Strategy Identification: Match each method to its description
1. Every single dollar is assigned a specific job until $0 remains unallocated. [ ]
Budgeting Learning Check Unit 3 • Business Math • Formative Assessment Score: ______ / 25 pts
Quick Check: Budgeting Principles & Math
Topic 2 Checkpoint: Show all mathematical formulas and calculate values carefully.
Name:
Date: Period:
1 Part 1: Budget Math Scenarios
12 Points
Calculate the values below based on a Gross Monthly Salary of $4,000.
1. What is the Net Monthly Income? [6 pts]
Formula: Gross Income - 25% Taxes
Taxes = $4,000 × 0.25
Net Income = $
2. What is the Suggested Rent Range? [6 pts]
Target Percentage: 25% to 28% of Net
Apply percentages to Net Income from Q1
Rent = $ – $
2 Part 2: Concept Verification (Circle TRUE or FALSE)
6 Points
Evaluate these common financial practices:
3. You should budget using Gross Salary.
"It represents your overall monthly take-home funds."
TRUE FALSE
4. Always reserve a Miscellaneous fund.
"Set aside 5% to 11% of net income for emergencies."
TRUE FALSE
3 Part 3: Budgeting Strategy Check
7 Points
5. In the 50/30/20 Plan, what do the three numbers represent?
50% =
30% =
20% =
6. Which method gives every single dollar a job until $0 is left over?
[ A ] Envelope Plan [ B ] Zero-Based Plan [ C ] Emergency Plan
Unit 3 • Topic 2: Quick Check • Budgeting Principles Total: 25 Points
Budgeting Teacher Guide Unit 3 • Business Math • Teacher Facilitation Guide Answer Key & Lesson Plan
Topic 2: Budgeting Principles & Modeling
Instructional pacing: 60–75 minutes • Calculators permitted
Covers Slides 12–22 & Strategy Pack
Prerequisites: Percent of a number & tax deductions
1. Foundations 15 Mins (Slides 12–13)
Needs vs wants, fixed vs variable, budgeting goals.
2. 3 Strategies 15 Mins (Strategy Slide)
50/30/20, Zero-based, and Envelope method.
3. Percentages & WE DO 20 Mins (Slides 14–17)
Professor & PTA salary conversions & ranges.
4. Quick Check & Project 15 Mins (Slides 18–22)
Quick Check & Personal Budgeting launch.
Guided Notes Answer Key (Filled Blanks in Bold Teal)
Slide 12: What is a Budget & Importance
• A budget estimates expected income , planned expenses , and savings goals . It acts as a financial road map .
• Income tracking = take-home pay. Budgeting gives intentional control ; prioritizes "paying yourself first ".
Slide 13 & Strategies: Needs vs Wants & 3 Strategies
• Needs are essential for survival ; Wants are not required . Fixed costs are identical ; Variable costs fluctuate .
• 50/30/20 Plan: 50% Needs, 30% Wants, 20% Savings.
• Zero-Based Plan: Give every dollar a job until $0 left over.
• Envelope Plan: Put real cash into envelopes. When empty, stop spending.
Slides 14–15: Suggested Percentages & Leftover Formula
• Percentages: Housing 25%-35% , Utilities 5%-10% , Car 10%-15% , Insurance 10%-20% , Entertainment 5%-10% .
• Leftover Surplus = Net Income - Total Expenditures . Emergency buffer goal: 20% ; Wants goal: 30% .
Slides 16–17: Modeling Walkthroughs
• Professor ($54,750): Gross/mo = $4,562.50 | Taxes (25%) = $1,140.63 | Net =
