Question

下面的简便运算怎么算啊，要过程。

64x15+64x25 4243-854-146 6300 ÷25÷4 3 .8x9.9+3.8x0.1 7 /16x10+7/16x6 (2/3+7/5-2/1)÷42/1

Answer 1

64x15+64x25 =64×（15+25）=64×40=2560 4243-854-146=4243-（854+146）=4243-1000=3243 6300 ÷25÷4 3 .8x9.9+3.8x0.1 =3.8×（9.9+0.1）=3.8×10=38 7 /16x10+7/16x6 =7/16×（10+6）=7/16×16=7 (2/3+7/5-2/1)÷42/1=（1+7/5）×42=42+7/5×42=42+30=72

Answer 2

64x15+64x25
=64x(15+25)
=64x40
=2560

4243-854-146
=4243-(854+146）
=4243-1000
=3243

6300 ÷25÷4
=6300÷(25×4)
=6300÷100
=63

3 .8x9.9+3.8x0.1
=3 .8x(9.9+0.1)
=3 .8x10
=38

7 /16x10+7/16x6
=7 /16x(10+6)
=7 /16x16
=7

(2/3+5/7-1/2)÷1/42
=(2/3+5/7-1/2)×42
=2/3×42+5/7×42-1/2×42
=28+30-21
=37

Answer 3

64x(15+25)=64x40=2560
4243-(854+146)=4243-1000=3243
6300÷(25x4)=6300÷100=63
3.8x(9.9+0.1)=3.8x10=38
7/16x(10+6)=7
1/15÷42=1/630