Show:
Mental Math
Expanded Form
Decompose Both Addends
100

What is the sum? 

129+10=?

129+10=139

100

What is the expanded form of 153

100+50+3

100

Decompose both addends to solve the equation.

237+141=


200+100=300

30+40=70

7+1=8

300+70+8=378

200

What is the sum? 

315+100=?

315+100=415

200

What is the expanded form of 638

600+30+8

200

Decompose both addends to solve

385+129=?

385+129=

300+100=400

80+20=100

5+9=14

400+100+14=514

300

What is the sum? 

459+100=?

459+100=559

300

What is the expanded form of 204

200+4

300

Decompose both addends to solve

341+125=?

300+100=400

40+20=60

1+5=6

400+60+6=466

400

What is the sum?

595+10=?

595+10=605

400

What is the expanded form of 985

900+80+5

400

Decompose both addends to solve

695+132=?

600+100=700

90+30=120

5+2=7

700+120+7=827

500

What is the sum? 

296+10=?

296+10=306

500

What is the expanded form of 706

700+6

500

Decompose both addends to solve

485+398=?

400+300=700

80+90=170

5+8=13

700+170+13=883