神马作文网9.9*2.5简便
来源：学生作业帮助网 编辑：作业帮 时间：2024/11/12 22:24:31
12.5*17+24*2.5-2.5简便12.5还可以看成2.5x5
(10-0.1)*2.5=10*2.5-0.1*2.5=25-0.25=24.75
9.9×9.9+0.99=9.9×9.9+9.9×0.1=9.9×(9.9+0.1)=9.9×10=99
99.9×9.9=(100-0.1)*9.9=100*9.9-0.1*9.9=990-0.99=989.01
=4.25*4*9.9/(2.5*4)+0.17=17*9.9/10+0.17=1.7*9.9+1.7*0.1=1.7*(9.9+0.1)=1.7*10=17
2.5×3.2×1.25=2.5×4×0.8×1.25=（2.5×4）×（0.8×1.25）=10×1=101.98×9.9=1.98×（10-0.1）=1.98×10-1.98×0.1=19.8-0
9.9×9.9+19.9=9.9×（10-0.1）+19.9=9.9×10-9.9×0.1+19.9=99-0.99+19.9=99+18.91=117.91
9.9*2.5=（10-0.1）*2.5=10*2.5-0.1*2.5=25-0.25=24.75
=72×(10-0.1)=72×10-72×0.1=720-0.72=712.8
2.5×0.32×1.25=（1.25×0.8）×（2.5×0.4）=1×1=1
4.9*9.9+0.49=4.9×9.9+4.9×0.1=4.9×（9.9+0.1）=4.9×10=49
4.25÷2.5×9.9+0.17=1.7×9.9+0.17=1.7×9.9+0.1×1.7=1.7×（9.9+0.1）=1.7×10=17
=1.6×4×2.5=1.6×（4×2.5）=1.6×10=16
8.7*9.9=8.7(10-0.1)=87-0.87=86.13
360.1/(10-0.1)再答：=360.1/10-360.1/0.1再答：=36.01-3601
"2.6×9.9=2.6×（10-0.1）=26-0.26=25.74"
4.3*（10-0.1）=4.3*10-4.3*0.1=43-0.43=42.57