Question

小学五年级脱式计算（必须要简便计算）

8.8*12.5*0.7 064*0.25*1.25*50 12.8+7.2*0.3
6.42*13.51+13.51*3.58 6.75*87.12-77.12*6.75 16-3.12*1.5

Answer 1

8.8×12.5×0.7
=（8 ×12.5）×（1.1×0.7）
=100×0.77
=77
0．64×0.25×1.25×50
=（0.8×1.25）×（4×0.25）×（0.2×50）
=1×1×10
=10
12.8+7.2×0.3（无法简便）
=12.8+2.16
=14.96
6.42×13.51+13.51×3.58
=（6.42+3.58）×13.51
=10×13.51
=135.1
6.75×87.12-77.12×6.75
=6.75×（87.12-77.12）
=6.75×10
=67.5
16-3.12×1.5（无法简便）
=16-4.68
=11.32

Answer 2

8.8*12.5*0.7
=(8+0.8)X12.5X0.7
=(8X12.5+0.8X12.5)X0.7
=(100+10)X0.7
=100X0.7+10X0.7
=77
064*0.25*1.25*50
=0.8X4X0.2X0.25X1.25X50
=(0.8X1.25)X(4X0.25)X(0.2X50)
=1X1X10
=10
12.8+7.2*0.3
=10+2.8+(10-2.8)X0.3
=10+2.8+3-2.8X0.3
=13+2.8X(1-0.3)
=13+2.8X0.7
=13+1.96
=14.96
6.42*13.51+13.51*3.58
=13.51X(6.42+3.58)
=13.51X10
=135.1
6.75*87.12-77.12*6.75
=6.75X(87.12-77.12)
=6.75X10
=67.5
16-3.12*1.5
=10+6-(4-0.88)x1.5
=10+6-(6-0.88x1.5)
=10+6-6+0.88x1.5
=10+(0.8+0.08)x1.5
=10+(1.2+0.12)
=10+1.32
=11.32