Post mental arithmetic shortcuts or tricks.
>You can multiply by 5 a big number quicker by multiplying it by 10 and dividing it in half from left to right.
>eg. 12389477*5
>123894770
>6 1 9 4 7 3 8 5
>You can multiply by 5 a big number quicker by multiplying it by 10 and dividing it in half from left to right.
>eg. 12389477*5
>123894770
>6 1 9 4 7 3 8 5
