掛け算の暗算方法（図式解法-1）

掛け算を暗算する為の図式解法。

Category:

Howto & Style

Tags:

• 数学
• 暗算
• 掛け算
• 算数
• mathematics
• graphical
• multiplication
• mental
• calculation

[kokikoki1207777]

nice good!!!!!!!!!

[mataroh]

In case of 4x4,

for example, number A is "4321" and number B is also "4321", the procedure is the below.

step1: 1 x 1

step2: 1 x 2 + 2 x 1

step3: 1 x 3 + 2 x 2 + 3 x 1

step4: 1 x 4 + 2 x 3 + 3 x 2 + 4 x 1

step5: 2 x 4 + 3 x 3 + 4 x 2

step6: 3 x 4 + 4 x 3

step7: 4 x 4

If multiplying 2 different digit numbers, each number of the empty digit place is to be seen as zero. So you can do it as like this movie.

[mingfreud]

It's nothing special... a very basical method.

[seance13]

ok this is good for 2x2 or 3x3 but what about 4x4 or even 3x2 or 4x3 and 4x2 grids?

[itigopanty]

テクニックでも何でもない、日本では標準的な計算の仕方だけど、­どこが「テクニック」なの？

[annxe]

I'll use calculator~

[zirusabc123]

what if they were 4 digits

[rob2581]

to fast but i got it

[riisevis]

bra jobba, mister.