Mental Math
Number Stories
Adding
100

 10 + 3 =?

3

100

Sally's ribbon is 32 inches long. Ava's ribbon is 14 inches long. Who's ribbon is longer? How much longer? 


Include a number model 

Sally's ribbon is longer. Her ribbon is 18 inches longer than Ava's.


32-14=?

14+?=32

100

31+27=? 

INCLUDE A BALLPARK ESTIMATE.

31+27=58

Ballpark Estimate: 30+30=60, 30+25=55

200

8+5=?

13

200

Barb had 16 shells from the beach. She found 7 more. How many shells does Barb have now? 


Include a number model. 

16+7=? 

Barb has 23 shells. 

200

34+41=? 


Include a ballpark estimate

34+41= 75


BE: 30+40=70 

300

7+6=?

13

300

Tom had 28 baseball cards. He got 3 from Jim. Then he gave 5 to his friend Bob. How many baseball cards does Tom have now?

Include number model(s). 

28+3= 31 

31-5= 26

or 

28+3-5= 26


Tom has 26 baseball cards now. 

300

47+29=?

47+29=76


400

9+6=?

15


400

Sarah is playing a board game with her sister. On her first turn, she earned 25 points. On her second turn, she lost 5 points. On her third turn she earned 14 points. How many points does she have now?


Include number model(s).

25-5=20

20+14=34

or 

25-5+14=?

She has 34 points now.

400

152+234=?

152+234=386

100+200=300

50+30=80

2+4=6

300+80+6

500

6+5=?

11

500

Olivia has 18 colorful pens. She gave 3 pens to Ziva. Then Olivia got 7 pens from Maizy. How many pens does Olivia have now? 


Include number model(s). 

18-3=15

15+7=22

or 18-3+7=22


Olivia now has 22 pens. 

500

189+298=?

189+298= 487

100+200=300

80+90=170

9+8=17

300+170+17=487