199加99乘99怎麼巧算?

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