Properties
Estimating
Adding 2 Digit Numbers
Adding 3 Digit Numbers
Adding 4 Digit Numbers
100
8+0=8
Identity
100
Round to the nearest ten. 24+51=
20+50=70
100
23+51=
74
100
123+431=
554
100
1,023+2,444=
3,467
200
4+3=7 3+4=7
Commutative
200
Round to the nearest hundred. 130+395=
100+400=500
200
54+61=
115
200
302+730=
1,032
200
4,023+2,512=
6,535
300
(5+2)+1=8
Associative
300
Round to the nearest ten. 97+69=
100+70=170
300
74+39=
113
300
520+489=
1,009
300
5,632+416=
6,048
400
100+0=100
Identity
400
Round to the nearest hundred. 451+572=
500+600=1,100
400
85+14=
99
400
566+819
1,385
400
6,701+231=
6,932
500
10+9=19 9+10=19
Commutative
500
Round to the nearest ten. 143+54=
140+50=190
500
68+89=
157
500
999+333=
1,332
500
9,999+3,278
13,277
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