Mental Math
Estimating
3 and 4 digit
Word Problems
Brain Breaks
100

Make a 10 or 100 to subtract mentally.

364 - 99 =

265

100

Estimate. Round each number to the indicated place value.

hundreds; 843 - 392 =

800 - 400 = 400

100

  287 - 113 = 


174

100

Determine whether and exact answer or an estimate is needed.

Marci wants to find out about how many more visitors came to the aquarium last month than this month.

Estimate.

100
Take a drink of water

Ahhh... Refreshing!

200

Make a 10 or 100 to subtract mentally.

1,980 - 528

1,452

200

Estimate. Round each number to the indicated place value. 

tens; 575 - 54 = 

580 - 50 = 530

200

600 - 452 =

148

200

Determine whether an exact answer or an estimate is needed. 

George is trying to figure out how much money he would have left in his savings after he buys a new lego set.

Exact

200

Stand up. Do 5 jumping jacks.

Sit down. Energized!

300

Subtract mentally by breaking apart the smaller number.

100 - 87

100 - 80 = 20

20 - 7 = 13

13

300

Estimate. Round each number to the largest place value.

718 - 36 =

700 - 40 = 660


300

7,350 - 803 = 

6,547

300

Nick wrote 993 pages of his new book on Monday. If he has completed a total of 2,040 pages by Tuesday, how many pages did he write on Tuesday?

2,040 - 993 = 1,047

300

Take 3 slow, deep breaths in through your nose, then out through your mouth.

Calming :)

400

Subtract mentally by breaking apart the smaller number.

98 - 24 =

98 - 20 = 78

78 - 4 = 74

74

400

Estimate. Round each number to the indicated place value.

tens; (193 - 34) - 17 =

(190 - 30) - 20 = ?

190 - 30 = 160

160 - 20 = 140

400

5,000 - 2,711 = 

2,289

400

Miss Day spends $2,000 on new school supplies for her class. If the new stools she bought cost $423, how much did the other supplies cost?

$2,000 - $423 = $1,577 

400

Stand up and do 5 toe touches.

Sit down. Energized!

500

Subtract mentally by breaking apart the smaller number.

673 - 13 =

673 - 10 = 663

663 - 3 = 660

660

500

Estimate. Round each number to the largest place value.

4,302 - 267 =

4,000 - 300 = 3,700

500

9,347 - 1,273 = 

8,074

500

The Bad Guys are fighting an army of 7,610 zombie kittens! If they have defeated 3,058 zombie kittens so far, how many more do they need to defeat?

4,552 zombie kittens.

500

Yoga Pose! Follow Miss Elliott's instructions.

Stretch and relax.