Adding Multiple Two-Digit Numbers by Decomposing

This lesson teaches how to add more than two two-digit numbers by decomposing them into tens and ones. It explains the commutative property of addition and provides examples using jelly beans and a bike trip to illustrate the concept. The lesson concludes with a summary of the decomposition method.

What is the commutative property of addition?

• Addition is only possible with whole numbers.

• The order of addends does not change the sum.

• The order of addends changes the sum.

• Addition of numbers always results in a larger number.

How can the number 23 be decomposed?

• Into 20 and 3

• Into 10 and 13

• Into 2 and 3

• Into 15 and 8

How many jelly beans did James eat in total?

• 58

• 88

• 68

• 78

What is the sum of the tens when decomposing 18, 24, and 36?

• 80

• 70

• 60

• 50

How many miles did Estefani ride in total during her trip?

• 55

• 45

• 75

• 65