（1）2.64×1.7-2.64×0.7
=2.64×（1.7-0.7）
=2.64×1
=2.64
（2）31.5×1.07-3.15×0.7
=3.15×10.7-3.15×0.7
=3.15×（10.7-0.7）
=3.15×10
=31.5
（3）2.7×5.7-2.7+5.3×2.7
=2.7×(5.7-1+5.3）
=2.7×10
=27
（4）0.625÷0.125×0.8
=（0.625×0.8）×8÷（0.128×8）
=0.5×8÷1
=4
（5）18.6×6.1+3.9×18.6
=18.6×（6.1+3.9）
=18.6×10
=186
（6）1.3579+3.5791+5.7913+7.9135+9.1357
=（1+3+5+7+9）×1.1111
=25×1.1111
=27.7775
（7）52.5x2.9+5.45
=5.25x29+5.25+0.2
=5.25×（29+1）+0.2
=5.25×30+0.2
=157.5+0.3
=157.7
（8）0.92x15+0.08x15
=（0.92+0.08）×15
=1×15
=15
（9）0.72×1.25×2.5
=0.9×（0.8×1.25）×2.5
=0.9×1×2.5
=2.25
（10）400.6x7-2003x0.4
=200.3x14-200.3x4
=200.3×（14-4）
=200.3×10
=2003
朋友,请及时采纳正确答案,下次还可能帮到您哦,您采纳正确答案,您也可以得到财富值,谢谢。
1.0.64×25×7.8+2.2
2.2÷2.5+2.5÷2
3.194－64.8÷1.8×0.9
4.36.72÷4.25×9.9
5.5180－705×6
6.24÷2.4－2.5×0.8
7.(4121+2389)÷7
8.671×15-974
9.469×12+1492
10.405×(3213-3189)
11.(25%-695%-12%)*36
12. 3/4*3/5+3/4*2/5
13. (1-1/4+8/9)/7/9
14 2/3+1/6/3/24+2/21
15 1*8/15*3/5
16 10-3/4/9/10-1/6
17 [(1/3+1/2)/5/6-1/3]/1/7
18 2/3/5+3/5/2+3/4
19 1/[(2-2/3/1/2)]*2/5