Hello, cUe?!

I assume we aren't allowed calculators . . .

What is remainder when is divided by 90 ?

Factor: .

This is: . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

Therefore: is amultipleof 90 . . . The remainder is 0.