Decomposing and Composing Numbers: Understanding the Parts of Numbers

This lesson covers the concepts of decomposing and composing numbers. It begins with an introduction to numbers and their parts using base ten blocks. The lesson explains how to decompose single-digit numbers like 5 and 7 into smaller units and explores multiple ways to do so. It then addresses common misunderstandings when decomposing two-digit numbers, using examples like 24 and 87. The lesson concludes with composing numbers, demonstrating how to combine smaller units to form larger numbers, both single-digit and two-digit. Overall, the lesson emphasizes understanding numbers as compositions of smaller parts.

What is one way to decompose the number 5?

• 1 ten and 5 ones

• 5 tens

• 3 tens and 2 ones

• 2 ones and 3 ones

How can the number 24 be correctly decomposed?

• 2 tens and 4 ones

• 4 tens and 2 ones

• 24 ones

• 2 ones and 4 ones

What is the correct decomposition of the number 87?

• 87 ones

• 8 tens and 7 tens

• 7 ones and 8 tens

• 8 ones and 7 tens

If you compose 3 ones and 5 ones, what number do you get?

• 8

• 85

• 35

• 53

How can you compose the number 49?

• 4 tens and 9 ones

• 9 tens and 4 ones

• 4 ones and 9 tens

• 49 ones