Show:
Adding 10 or 100 and Base Ten Blocks (9.1, 9.2, 9.3)
Decomposing One and Two Addends (9.4 + 9.5)
Adjusting Addends (9.6)
Explain Addition Strategies (9.7)
100

Add 10 to 568.

568+10=578

100

Decompose both addends to solve: 

342+132=

342=300+40+2; 132=100+30+2

100+300=400; 40+30=70; 2+2=4

400+70+2=472

100

When we adjust addends to add, we use numbers that have a 0 in the ones place. What are these numbers called?

Friendlier numbers

100

When you adjust addends, are: 

a. both addends added to

b. both addends subtracted from 

c. one addend is added to and one is subtracted from

The answer is C. What is added to one addend must be subtracted from the other addend. 

200
Add 100 to 347.

347+100=447

200

Decompose one addend to solve: 

458+210=

458= 400+50+8

210+400=610; 610+50=660; 660+8=668

458+210=668

200

Solve this problem by adjusting addends: 

186+297=

186 + 297 = 

-3      +3

183 + 300= 483

200

What strategy is shown below:

458+210=?

458= 400+50+8

210+400=610; 610+50=660; 660+8=668

458+210=668

Decomposing one addend.

300

Add 10 to 497.

497+10=507

300

Decompose both addends to solve:

349+572=

349= 300+40+9; 572=500+70+2

300+500=800; 40+70=110; 9+2=11

800+110= 910; 910+11= 921

349+572=921

300

What is the sum? Adjust the addends.

503+364=

503+364=

-3     +3

500+367= 867

300

What strategy is shown here: 

186 + 297 = 

-3      +3

183 + 300= 483

Adjusting addends

400

Use base ten blocks to solve. 

458+321=

☐ ☐ ☐ ☐ lllll ********

☐ ☐ ☐ ll *

☐ ☐ ☐ ☐ ☐ ☐ ☐  lllllll *********=779


400

Decompose one addend to solve: 

289+644=

644=600+40+4

289+600= 889; 889+40=939; 939+4=943

289+644=943

400

Solve this problem by adjusting addends: 

395+528=

395+528=

-2      +2

393+ 530= 923

400

Joe is solving the problem 732+122. He solves it below: 

732+122=

-2      -2

730+ 120= 850

Did he solve it correctly?

He did not, he adjusted both by subtracting. When you adjust, you must add to one addend and subtract the other.

500

Use base ten blocks to solve. 

399+132=

☐ ☐ ☐ lllllllll *********

☐ lll **

***********= l *; llllllllllll= ☐ ll

☐ ☐ ☐ ☐ ☐  lll * = 531

500

What is a strategy/tool you can use when you decompose only one addend?

You can use a number line.

500

How can you adjust the addends? (2 answers)

277 + 398=

a. 280+395                   b. 280+401

c. 275+400                   d. 275+396

The answer is A and C.

500

Which two equations will require regrouping? 

a. 341+211       b. 456+399

c. 652+317       d. 387+276

Both B and D