1 Answer

Dpedoneze · Answer 1 · 2021-03-14T03:30:19+0000

You may write them separating the units and tens digits, and then use FOIL to add 4 easy tems. For example, let's compute
$21\cdot 36$ :

$21\cdot 36=(20+1)(30+6)=600+120+30+6 = 756$

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