vocabulary
加
add/plus
12 × 4× 25 = 12 × （4× 25），which law did it use？
associative law of multiplication
38×4+38×16=
38×（4+16）
=38×20
=760
13✖144=
1872
因数
factor
Using the distributive law which option is the same as c × b + c × a.
A. a×（b ＋ c）
B. b × ( a + c）
C. c × ( a + b）
D. 2(b + c)
C
151+74+26=
251
25×（4+10）=
25×4+25×10
=100＋250
=350
78 times 101 equals？
7878
加法交换律
commutative law of addition
Give an example for the commutative law.
...
162+205+38+55=
200+260=460
41×99+41=
41×（99+1）=4100
759 divided by 23 equals？
33
乘法结合律
associative law of multiplication
Solve 66 × 25× 8 using the associative law.
66 ×25 ×8 = 66 ×（25 ×8）
= 66 × 200 =13200
8 × 20 × 13× 5=
10400
88×102=
88×100+88×2
=8800+176
=8976
The dividend is 650 and the divisor is 40. What is the quotient and remainder？
16R10
乘法分配律
distributive law of multiplication
Solve 31 × 125 × 3 × 8
（31 × 3） × （125× 8）=93×1000=93000
17 × 25 + 25 × 23
1000
99×75
99×75
=(100-1)×75
=100×75-1×75
=7500-75
=7425
723➗77≈
9