subtract
31-22=
9
32+66=
98
An ___________ is a number close to the an exact amount.
Estimate
Estimate then add:
34 + 22=
30+20= 50
Round to the nearest hundreds:
456
500
57-45=
12
135+67=
202
The ___________________________ states that you can add two or more numbers in any order and get the same sum.
Commutative Property
Estimate then add:
67+55=
70+60= 130
Round to the nearest hundred:
745
700
80-67=
13
356+234=
590
The _____________________________ states that you can group addends in different ways and still get the same sum.
Associative Property
Estimate then add:
456+321=
500+300=800
Round to the nearest ten:
678
680
123-89=
34
567+456=
1,023
The answer to an addition problem
Sum
Estimate then subtract:
89-34=
90-30=60
Round to the nearest ten
123
120
704-356=
348
598+321=
919
The answer to a subtraction problem
Difference
Estimate then subtract:
467-222=
500-200=300
Round to the nearest thousands:
1568
2000