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Round to Add
Round to Subtract
Partial Sums and Addition
Partial Differences and Subtraction
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100

Round to the nearest 10. Then add to find the sum.

135+152

140+150=290

100

Round to nearest 10, then find difference.

856-328

860-330=530

100

Add.

123+452

100+400=500

20+50=70

3+2=5

575

100

Subtract.

416-243

416-200=216

216-40=176

176-3=173

100

How many planets are in our solar system?

8.  If you counted Pluto as a dwarf planet that would make it 9.  

200

Round to the nearest hundred.  Then Add to find the sum.

535 + 423

500+400=900

200

Round to nearest 100, then find difference.

526-207

500-200=300

200

Add.

412+273


400+200=600

10+70=80

2+3=5

685

200

Subtract.

856-243

856-200=656

656-40=616

616-3=613

200

Which planet is closest to the sun?

Mercury

300

Round to nearest 10 then find the sum.

236 + 217

240+220= 460

300

Round to nearest 10, then find difference.

863-526

860-530=330

300

Add.

412+273+139

400+200+100=700

10+70+30=110

2+3+9=14

824

300

Subtract.

220-180


220-180=40  

Make sure students show work.

300

What needs to be broken before you can use it?

An egg.
400

Round to nearest 100, then find sum.

407+326

400+300=700

400
Round to nearest 100, then find difference.

748-229

700-200=500

400

Add. 

124+32+238

100+200+0=300

20+30+30=80

4+2+8=14

384

400

Solve in any way you choose.

657-122

657-122=535

400

What is the largest planet in our solar system?

Jupiter

500

Estimate.

196+243

200+240=440

200+200=400

500

Estimate.

489-253

500-300=200

490-250=240

500

125+221+302+443

100+200+300+200=800

20+20+0+40=80

5+1+2+3=11

891


500

Solve in any way you choose.

400-225

400-225=175

500

What is the tallest mountain in the world?

Mt. Everest located in the Himalayas on the border of Nepal and China.