Mental Math
Rounding Whole Numbers and Decimals
Addition of Decimals
Problem Solving
Subtraction of Decimals
100

Double Points (200 points)

Use mental math to add 2.1+0.9+1.2

4.2

100
Round to the nearest ten: 17
20
100

Double Points (200 points)

Find the sum: 3.28+6.09

9.37

100

Double Points (200 points)

Nate has a $5 bill and a $10 bill. He spends $2.50 on a smoothie and $2 for a muffin. How much money does he have left?

$10.50

100
Rose needs 22 hamburgers for a party. She has made 12 hamburgers so far. How many more does Rose need to make? Draw a picture to help!
10 more hamburgers
200
Use mental math to subtract 8.6-4.9
3.7
200
Round to the nearest ten thousand 427,468
430,000
200

Double Points (400 points)

Find the sum: $44.00+$91.46

$135.46

200

Double Points (400 points)

Lonny planted 15 roses, 12 geraniums and 6 daises. His dog digs up 4 roses and 2 daisies. How many flowers are left?

27 flowers

200
Find the difference: 7.21-6.1
1.11
300

Double Points (600 points)

Use mental math to subtract 4.25-3.08

1.17

300
Round to the nearest whole number: 643.82
644
300

Double Points (600 points)

Juan adds 3.8+4.6 and gets a sum of 84. Is his answer correct? Write how you know.

No he is not correct because 84 is not close to the estimated answer of 4+5. He forgot to add the decimal point, so the sum should be 8.4

300
Elias saved $30 in July, $21 in August and $50 in September. He spent $18 on movies and $26 on gas. How much money does Elias have left?
$57
300

Double Points (600 points)

Find the difference: $4.08-$2.12

$1.96

400

Use mental math to add $3.47+$4.35

$7.82

400

Double Points (800 points)

Round to the nearest hundredth: 0.757

0.76

400
What is the sum of 45.09+2.005
47.095
400

Double Points (800 points)

A mason needs 22 bricks to make a stoop. So far, he has carried 15 to the site. How many more bricks must he carry? Draw a picture, write an equation and solve.

7 bricks

400
The pyramid measured 143.5 meters high. The other pyramid measures 65.5 meters high. What is the difference in the heights of the two pyramids?
78 meters
500

Double Points! (1,000 points)

On 3 different days at her job, Anne earned $27.50, $33.75 and $49.25. She needs to earn $100 to buy a new phone. The cost of the desk includes tax. If she buys the desk, how much money will she have left over?

$10.50

500
The world's largest blanket measures 4.26 meters around. Round 4.26 to the nearest ones place and to the nearest tenths place.
4 4.3
500

A balloon mural of the Chicago skyline measures 17.6m on one side and 26.21m on the other two sides. What is the perimeter of the mural?

87.62m

500
Dayana picked apples for 2 hours. She picked 28 apples in the first hour and at the end of 2 hours she had 49 apples. How many apples did she pick during the second hour?
21 apples
500

Double Points (1,000 points)

An average person's leg bone measures 19.88 inches and the lower leg bone measures 16.94 inches. How much longer is the upper leg bone then the lower leg bone?

2.94 inches

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