Algorithm Masters Worksheet
Algorithm Masters: 3-Digit Addition
Standard US Algorithm • Composing Tens & Hundreds
Name:
Date:
REMEMBER Add column by column starting at the ones.
10 Ones = Compose 1 Ten | 10 Tens = Compose 1 Hundred
Problem 1 Compose Ones
H T O
3 4 8
Did you compose a new group?
Ten Hundred
Problem 2 Compose Tens
H T O
4 6 2
Did you compose a new group?
Ten Hundred
Problem 3 Compose Ones & Tens
H T O
5 3 7
Did you compose a new group?
Ten Hundred
Problem 4 Compose Ones & Tens
H T O
2 6 9
Did you compose a new group?
Ten Hundred
Problem 5 Compose Ones & Tens
H T O
6 5 8
Did you compose a new group?
Ten Hundred
Place Value Deconstruct
Look at Problem 5. Show how you composed the numbers into Hundreds, Tens, and Ones:
8 ones + 4 ones = 1 ten and 2 ones
1 ten + 5 tens + 9 tens = 1 hundred and 5 tens
1 hundred + 6 hundreds + 1 hundred = 8 hundreds
Addition Subtotal: _____ / 5 Correct
Part 1: 3-Digit Addition (US Algorithm) Page 1 of 2
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Algorithm Masters: 3-Digit Subtraction
Standard US Algorithm • Decomposing Tens & Hundreds
Name:
Date:
REMEMBER More on the floor? Go next door and decompose (trade)!
Decompose 1 Ten → 10 Ones | Decompose 1 Hundred → 10 Tens
Problem 6 Decompose Tens to Ones
H T O
6 5 2
− 3 2 7
What did you decompose?
1 Ten 1 Hundred
Problem 7 Decompose Hundreds to Tens
H T O
8 2 5
− 4 6 1
What did you decompose?
1 Ten 1 Hundred
Problem 8 Decompose Tens & Hundreds
H T O
7 4 3
− 2 6 8
What did you decompose?
1 Ten 1 Hundred
Problem 9 Decompose Tens & Hundreds
H T O
6 1 4
− 2 8 5
What did you decompose?
1 Ten 1 Hundred
Problem 10 Challenge: Across Zero
H T O
9 0 5
− 4 3 8
What did you decompose?
1 Ten 1 Hundred
IEP Goal Progress Tracker Special Ed Record
“Given 10 addition and/or subtraction problems within 1000, student will correctly de/compose numbers and solve using US Algorithm.”
Addition
____ / 5
Subtraction
____ / 5
Total Mastery
____ / 10
De/composition verified: Yes Partial No
Prompting Level: [ ] Ind [ ] Gest [ ] Verb [ ] Mod
Evaluator: __________________ Acc: _____ %
Part 2: 3-Digit Subtraction (US Algorithm) Page 2 of 2
