Digit Multiply Slides
Grade 4 Math • Operations & Place Value
Lesson Deck
Multiplication Power
Step-by-step mastery: Multiplying 2-digit numbers by 1-digit numbers with regrouping.
1
Multiply the Ones
2
Regroup the Tens
3
Multiply & Add Tens
CONCEPT
What Does 24 × 3 Really Mean?
Place Value Breakdown
Break it apart into Tens and Ones:
24 = 2 Tens (20) + 4 Ones (4)
Multiply the Ones: 3 × 4 = 12
Multiply the Tens: 3 × 20 = 60
Combine Both Parts: 60 + 12 = 72
The Vertical Algorithm
Instead of writing long addition every time, the standard vertical algorithm combines these steps into one quick, smooth process!
We work from RIGHT to LEFT:
1. Ones Column → 2. Tens Column
Always start multiplication in the smallest place value (the ones place)!
STEP 1
Multiply the Ones & Regroup
Problem: 36 × 4
+2
36
× 4
_4
Action: 4 × 6 ones = 24 ones
Since 24 has 2 tens and 4 ones, you cannot put both digits in the ones place!
Write Down 4
The 4 stays in the ones column of your answer.
Carry (Regroup) 2
Place the 2 tens above the 3 in the tens column.
Remember: Only one single digit can sit in the ones place!
Next: We multiply the tens place and add that carried 2!
STEP 2
Multiply the Tens & Add the Regrouped Digit
Problem: 36 × 4
+2
36
× 4
144
Two Quick Calculations in the Tens Place:
A Multiply first: 4 × 3 = 12 tens
B Add carried: 12 + 2 = 14 tens
Common Mistake to Avoid!
DO NOT add 3 + 2 first to get 5, then multiply! Always MULTIPLY FIRST, then ADD the carried number.
Final Answer: 36 × 4 = 144. Perfectly solved!
GUIDED PRACTICE 1
Let's Solve Together: 27 × 3
Follow the 2 Steps
+2
27
× 3
81
Question 1: Multiply the Ones
3 × 7 = 21
Write down 1 in the ones column, carry +2 above the tens column.
Question 2: Multiply & Add the Tens
3 × 2 = 6 → 6 + 2 = 8
Write down 8 in the tens column.
Total Product: 81
Great job! Let's try one with a 3-digit answer!
GUIDED PRACTICE 2
Stepping Up: 58 × 4
Bigger Regrouping
+3
58
× 4
232
Step 1: Multiply Ones
4 × 8 = 32
Keep the 2 in the ones column, carry +3 to the tens column.
Step 2: Multiply Tens & Add Carried
4 × 5 = 20 → 20 + 3 = 23
Write down 23. The product expands into the hundreds place!
Total Product: 232
Place value rule: If there are no more columns to multiply, write the full number (23) in the product!
CHECKLIST
3 Golden Rules for 100% Accuracy
Keep in Mind
1. Line Up Columns
Keep your ones over ones and tens over tens. Messy columns lead to messy math!
Tip: Use grid paper to keep columns neat.
2. Write Small Carries
Write your regrouped digit clearly at the top with a + sign so you don't forget to add it!
Tip: Cross it out once you add it.
3. Multiply Then Add
Always multiply the tens first. Never add the carried number before multiplying!
Tip: Say it out loud: "Multiply, then add!"
Follow these three steps on every problem for guaranteed success!
Ready for Action
Independent Work Time
Time for Your Independent Practice!
Grab your practice worksheet. You have 10 dedicated practice problems with ample space to show your regrouping and step-by-step calculations.
✓
Show all carried digits in the top boxes
✓
Double check each step before moving on
Multiplication Power Series Good luck mathematicians!
Digit Blast Worksheet
Grade 4 Math • Operations & Algebraic Thinking
Double Digit Multiply | Step-by-Step Guide
Name:
Date: Score:
HOW TO MULTIPLY A 2-DIGIT NUMBER BY A 1-DIGIT NUMBER
Standard Algorithm
1
Step 1: Multiply the Ones
Multiply the bottom digit by the top ones digit.
If ≥ 10, write the ones digit down & carry the tens digit to the carry box.
2
Step 2: Multiply Tens & Add Carried
Multiply the bottom digit by the top tens digit.
Add the carried number to this product, then write the total in front.
Golden Rule: Always multiply first, and then add the carried number. Never add first!
Part 1: Guided Practice Walkthrough
Follow each prompt to calculate the steps
Problem 1 24 × 3
+1
24
× 3
1. Multiply Ones:
3 × 4 =
Write , carry 1 ten.
2. Multiply Tens & Add:
3 × 2 =
(3 × 2) + 1 =
Final Answer: Product = ________
Problem 2 35 × 4
+__
35
× 4
1. Multiply Ones:
4 × 5 =
Write , carry .
2. Multiply Tens & Add:
4 × 3 =
(4 × 3) + carried =
Final Answer: Product = ________
Problem 3 48 × 3
[ ]
48
× 3
1. Multiply Ones:
3 × 8 =
Write ones, carry tens.
2. Multiply Tens & Add:
3 × 4 =
Add carry:
Final Answer: Product = ________
Problem 4 67 × 5
[ ]
67
× 5
1. Multiply Ones:
5 × 7 =
Write ones, carry tens.
2. Multiply Tens & Add:
5 × 6 =
Add carry:
Final Answer: Product = ________
Page 1 of 3 • Guided Practice Walkthrough
Independent Mastery • Part A
Independent Practice: Problems 1 to 5
Name:
Directions: Multiply each problem using the standard algorithm. Write any regrouped digits in the carry box above the tens column. Show all your calculation work in the blank workspace.
Digit Blast Answer Key
Teacher Edition • Complete Worked Solutions
Double Digit Multiply | Answer Key & Guide
Assessment Focus
4.NBT.B.5 Standards
Part 1: Guided Practice Solutions
4 Problems • Page 1 of Student Sheet
Prob 1: 24 × 3 = 72
[+1]
24
× 3
72
• Ones: 3 × 4 = 12
• Carry: 1 ten
• Tens: (3 × 2) + 1 = 7
Prob 2: 35 × 4 = 140
[+2]
35
× 4
140
• Ones: 4 × 5 = 20
• Carry: 2 tens
• Tens: (4 × 3) + 2 = 14
Prob 3: 48 × 3 = 144
[+2]
48
× 3
144
• Ones: 3 × 8 = 24
• Carry: 2 tens
• Tens: (3 × 4) + 2 = 14
Prob 4: 67 × 5 = 335
[+3]
67
× 5
335
• Ones: 5 × 7 = 35
• Carry: 3 tens
• Tens: (5 × 6) + 3 = 33
Part 2: Independent Practice Solutions (Problems 1 to 5)
Page 2 of Student Sheet
#1 23 × 3
[—]
23
× 3
69
Key Step: No regrouping needed. 3×3=9, 3×2=6 tens.
Ans: 69
#2 42 × 4
[—]
42
× 4
168
Key Step: 4×2=8. 4×4=16 tens, creates hundreds digit 1.
Ans: 168
#3 28 × 3
[+2]
28
× 3
84
Key Step: 3×8=24 (carry 2). (3×2)+2 = 6+2 = 8 tens.
Ans: 84
#4 46 × 2
[+1]
46
× 2
92
Key Step: 2×6=12 (carry 1). (2×4)+1 = 8+1 = 9 tens.
Ans: 92
#5 37 × 4
[+2]
37
× 4
148
Key Step: 4×7=28 (carry 2). (4×3)+2 = 12+2 = 14 tens.
