Adding Four Two-Digit Numbers by Decomposing

This lesson teaches how to add four two-digit numbers by decomposing them into tens and ones. It begins with an explanation of decomposing and the commutative property of addition. Two examples are provided, involving the addition of numbers representing tomatoes picked by a farmer over two weeks. Each example demonstrates breaking down numbers into tens and ones, adding them separately, and then combining the sums to find the total. The lesson concludes with a summary of the decomposing method.

What is decomposing in mathematics?

• Combining numbers to form a larger number

• Taking apart a number into smaller parts

• Multiplying numbers to get a product

• Dividing numbers to get a quotient

Which property states that the order of addends does not change the sum?

• Identity Property

• Commutative Property

• Distributive Property

• Associative Property

How many tomatoes did the farmer pick in total during the first week?

• 86

• 98

• 104

• 112

What is the sum of the tens when decomposing the numbers 33, 24, 17, and 12?

• 60

• 70

• 80

• 90

How many tomatoes did the farmer pick in total during the second week?

• 76

• 82

• 92

• 86