Question

用简便方法计算（用递等式）

① 392.6×192 —39260×0.92

② 7.5×23+31×2.5

③ 0.79×0.46＋7.9×0.24＋11.4×0.079

Answer 1

你好，莉莉_Cc

① 392.6×192 -39260×0.92
=392.6×192-392.6×92
=392.6×(100+92)-392.6×92
=392.6×100+392.6×92-392.6×92
=39260

② 7.5×23+31×2.5
=2.5×3×23+31×2.5
=2.5×69+31×2.5
=2.5×(69+31)
=2.5×100
=250

③ 0.79×0.46＋7.9×0.24＋11.4×0.079
=0.79×0.46+0.79×2.4+1.14×0.79
=0.79×(0.46+2.4+1.14)
=0.79×4
=3.16

Answer 2

(1)=39260×1.92-39260×0.92=39260×(1.92-0.92)=39260
(2)=2.5×3×23+2.5×31=2.5×(69+31)250
(3)=0.79×0.46+0.79×2.4+0.79×1.14=0.79×(0.46+2.4+1.14)=0.79×4.3=3.397