Module 4Lesson 9

Objective

0 Use math drawings to represent the composition when adding a two-digit to a three-digit addend.

Application Problem0 Marla spilled a box of paper clips.

They landed on her desk and on the floor. 20 of them landed on her desk, and 5 more fell on the floor than landed on her desk. How many paper clips did she spill?

Fluency Practice0Say the number in standard form. Ready?03520Say the number in expanded form. Ready?0300 + 50 + 20Say the number Say Ten way03 hundreds, 5 tens, 2 ones0What is 20 more than 352?0372

20 less? 100 more? 100 less?

102 less? 220 less? 510 more?

Concept Development0Write 34 + 18 the vertical way on your paper. 0Now draw a model using a place value chart like this

one. Label the tens and ones. This means we don’t have to label the disks, because a disk in the ones place is a one, and a disk in the tens place is a ten. The place tells us the value, or how much the disk is worth.

0Now draw a model of each addend. Start with the top number.

0Now the bottom addend0Check your model

10’s 1’s

3 4+ 1 8

Concept Development0What is 4 ones + 8 ones? 0 12 ones! Did you notice anything about your ones? 0Bundle! Circle ten ones as one 10 0Write a 1 on the line below the tens place, and write 2

under the line below the ones place.0Now we add the tens. 0So 34 + 18 equals 52. 10’s 1’s

3 4+ 1 8

Concept Development0Write 134 + 18 the vertical way on your paper0What is 4 ones + 8 ones? 0 12 ones! Did you notice anything about your ones? 0Bundle! Circle ten ones as one 10 0Write a 1 on the line below the tens place, and write 2

under the line below the ones place.0Now we add the tens.0Now add the hundreds 0So 134 + 18 equals 152.

100’s 10’s 1’s

1 3 4 + 1 8

Concept Development0Now you try.0 Solve 134 + 18

Problem Set0 Do your best to complete the Problem Set within 10 minutes.0 Use the RDW approach to solve story problems.