mental math
I know that
x times 5=(10x)/2
basically, to multily something by 5, divide it by 2 then multily it by 10
198/2=99
times 10
990
I think the distribitive peroperty part is
198=200-2
so
remember
a(b-c)=ab-ac
so
5(200-2)=
(5)(200)-(5)(2)=
1000-10=
990
