Question

用简便方法计算1，4.7十7.69十5.3十2.31 57x101一57

Answer 1

4.7+7.69+5.3+2.31
=(4.7+5.3)+(7.69+2.31)
=10+10
=20
57×101-57
=57×(101-1)
=57×100
=5700

Answer 2

4.7十7.69十5.3十2.31
=4.7+5.3+7.69+2.31
=10+10
=20
57x101一57
=57*100
=5700

Answer 3

(一3.14)x35.2十6.28x(一23.3)一1.57x36.4=(一3.14)x35.2十3.14*2x(一23.3)一1.57*2/2*36.4=-3.14[35.2+2*23.3+36.4/2]=-3.14[35.2+2*23.3+18.2]=-3.14[35+0.2+46+0.6+18+0.2]=-3.14[35+46+18+0.2+0.6+0.2]=-3.14[35+46+18+1]=-3.14[36+46+18]=-3.14[30+6+40+6+20-2]=-3.14[30+40+20+6+6-2]=-3.14[90+10]=-3.14*100=-314