Question

4*5=15
7*2=12
2*8=08
20*10=???

Answer 1

First number is reduced by 1 and then multiplied.
4-1 x 5 =3 x 5=15
7-1 x 2 =6 x 2=12
2-1 x 8 = 1 x 8=8
therefore,
20-1 x 10= 19 x 10 =190