Show:
Properties
Mental Math to Add
Mental Math to Subtract
Estimating Sums
Estimating Differences
100

Which property is shown in this addition sentence: 6+0=6

Identity (Zero) Property

100

Use mental math to find the sum.
37+16=


53

30 + 10=40

7+6= 13

30+13=53

100

Tyrell saved $73.
He spent $28 on a watch.
Use mental math to figure out how much money Tyrell has left.

45 Dollars

100

Round to the nearest ten to estimate.
31+66=

100

100

A gardener has 77 flowers. He plants 58 of the flowers.
Which is the best estimate of the number of flowers the gardener has left to plant?

20 flowers

200

Find the sum:

(8 + 6) + 7=

21

200

Lorna is playing a game.
She gets 13 points on her first turn.
She gets 17 points on her second turn.
Use mental math to find her score so far.


  • A.31
  • B.30
  • C.29
  • D.20


B. 30

200

The price of a CD player was $60.
It is now on sale for $22 less than the original price.
Which number sentence could you use to show how to find the sale price of the CD player?

  • A.$60 – $22 = ?
  • B.$60 + $22 = ?
  • C.$60 – ? = $20
  • D.? – $22 = $60


A

200

Jed is in a flying disk contest.
His first throw goes 97 feet.
His next throw goes 128 feet.
Which number sentence shows the best way to estimate the total distance of both throws?


  • A.90 + 120 = 210
  • B.100 + 200 = 300
  • C.100 + 120 = 220
  • D.100 + 130 = 230


D. 230

200

On Saturday, 376 children and 132 adults visited the zoo.
Round to the nearest hundred to estimate the difference in the number of children and adults who went to the zoo that day.

300 children

300

Which property of addition is shown in the number sentence:

4+(1+5)= (4+1)+5

The Associative (Grouping) Property
300

Use mental math to find the sum.
57 + 18 = ?


75

300

Use mental math to find the difference.
64−26=

38

300

The table shows how many books are in a class library.
Which is the most reasonable estimate of the total number of poetry and biography books?

Type of Book

Fiction 223

Poetry51

Biography146

Science53 

C. 200

300

The lunchroom has 142 seats.
Children are sitting in 87 of the seats.
Which is the best estimate of the number of empty seats?

50 empty seats

400

Which property does this represent:

2+7=7+2

Commutative (Order) Property

400

Use breaking apart to add 36 + 24.
Which expression does NOT show a correct way to do this?

  • A.3 + 6 + 2 + 4
  • B.30 + 6 + 20 + 4
  • C.36 + 20 + 4
  • D.30 + 20 + 6 + 4


A.

400

Nora's soccer team needs $52 to buy enough pizzas for the team.
They have already collected $45.
Use mental math to figure out how much more money the team needs.

7 dollars

400

Round to the nearest hundred to estimate.
504+310=

800

400

At a party, 26 people ate in the house and 49 people ate in the yard.
Which number sentence shows the BEST way to estimate how many fewer people ate in the house than in the yard?

  • A.30 + 50 = 80
  • B.50 – 20 = 30
  • C.50 – 25 = 25
  • D.49 – 26 = 23


C. 50-25

500

Which number represents the question mark to make the number sentence true? 5 + (3 + ?)= (2+3) +5

2

500

The Martinez family drove 48 miles to visit a national park.
Then they drove another 32 miles to visit an amusement park.
Use mental math to figure out how many miles the Martinez family drove in all.


  • A.70 miles
  • B.76 miles
  • C.80 miles
  • D.88 miles


C. 80 Miles

500

Use mental math to find the difference.
81−29=

52

500

Kara has 72 stickers. Her sister has 148 stickers.
Use compatible numbers to estimate how many stickers Kara and her sister have altogether.

220 stickers

500

The school drama club has 422 tickets to sell for the play.
They have already sold 280 tickets.
Which is the best estimate of how many tickets are left?

100 Tickets