# Strategies for Composing Tens

Examples and solutions to help Grade 2 students learn how to use mental strategies to relate compositions of 10 tens as 1 hundred to 10 ones as 1 ten.

Common Core Standards: 2.NBT.6, 2.NBT.7, 2.NBT.8, 2.NBT.9

### NYS Math Module 4 Grade 2 Lesson 17

Lesson 17 Problem Set

1. Solve mentally.
a. 2 ones + ________ = 1 ten, 2 + ________ = 10
2 tens + ________ = 1 hundred, 20 + ________ = 100
b. 1 ten = ________ + 6 ones, 10 = ________ + 6
1 hundred = ________ + 6 tens, 100 = ________ + 60
2. Solve mentally.
a. 3 ones + 7 ones = ________ , 3 + 7 = _________
3 tens + 7 tens = ________ , 30 + 70 = ________
13 tens + 7 tens = ________ , 130 + 70 = ________
b. 6 ones + 4 ones = ________ , 6 + 4 = _________
16 tens + 4 tens = ________ , 160 + 40 = ________
3. Solve.
a. 9 ones + 4 ones = ____ ten ____ ones, 9 + 4 = _________
9 tens + 4 tens = ____ hundred ____ tens, 90 + 40 = ________
b. 4 ones + 8 ones = ____ ten ____ ones, 4 + 8 = _________
4 tens + 8 tens = ____ hundred ____ tens, 40 + 80 = ________
4. Fill in the blanks. Rewrite each as an addition sentence with two parts. Use the arrow method.

Lesson 17 Homework

2. Solve mentally.
a. 2 ones + 8 ones = ________
2 + 8 = _________
2 tens + 8 tens = ________
20 + 80 = ________
b. 5 ones + 6 ones = ________
5 + 6 = _________
5 tens + 6 tens = ________
50 + 60 = ________
c. 14 ones + 4 ones = ________
14 + 4 = _________
14 tens + 4 tens = ________
140 + 40 = ________

3. Solve.
a. 6 ones + 5 ones = __ ten __ one
6 + 5 = _________
6 tens + 5 tens = __ hundred __ ten
60 + 50 = ________
b. 5 ones + 7 ones = __ ten __ ones
5 + 7 = _________
5 tens + 7 tens = __ hundred __ tens
50 + 70 = ________
c. 9 ones + 8 ones = __ ten __ ones
9 + 8 = _________
9 tens + 8 tens = __ hundred __ tens
90 + 80 = ________

4. Fill in the blanks. Rewrite each as an addition sentence with two parts.

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