Estimate by rounding to the nearest hundred
523
+274
-------
500+300=800
Solve by rounding to the nearest ten
87
-23
------
90-20=70
Use mental math to solve:
56-21=_____
35
Solve using mental math:
24+35=
59
How would you solve this using break apart?
47+52=___
40+50=90
7+2=9
90+9=99
Which property is this?
567+0=567
Identity property/zero property
Which property is this?
(3+6)+2=3+(6+2)
Associative property
Which property is this?
4+5=5+4
Commutative property
Which property is this?
73+32=32+73
Commutative property
Which property is this?
123+(456+361)=(123+456)+361
Associative property
Which property is this?
0+271=271
Identity property/zero property
Estimate by rounding to find the answer
325
+264
------
300+300=600
330+260=590
Estimate the answer
579
-157
------
600-200=400
580-160=420
Mrs Romo wants to buy 53 pencils. She already bought 21. Which number sentence shows how many more pencils she needs?
A) 21+___=53
B) 53+21=___
C) ___-21=53
D) 53-___=21
A or D
Natalia has 23 donuts. Danielle has 12 donuts. Which number sentence shows how many more donuts Natalia has?
A) 12-23+___
B) 23-___=12
C) 12+___=23
D) 23-12=___
C or D
