199加99乘99怎麼巧算?
199加99乘99
=199+99×99
=100+99+99×99
=100+99×100
=100×(1+99)
=100×100
=10000
1024乘15等於幾
1024乘15
=1024×(10+5)
=1024×10+1024×5
=10240+5120
=15360
1024乘625乘1331等於?(簡便算灋)
1024x625x1331=64x(16x625)x11x11x11=64x10000x11x11x11=704x11x11x10000=7744x11x10000=85184x10000=851840000
注意一個數與11相乘是非常簡單的,如:7744x11=7744x(10+1)=77440+7744=85184