Question

Which is bigger 40% of 90 or 1/2 of 80?

Answer 1

$40\%\cdot90=0.4\cdot90=36\\ \dfrac{1}{2}\cdot80=40\\\\ 40>36\\ \Downarrow\\ \boxed{\dfrac{1}{2}\cdot80>40\%\cdot90}$

Answer 2

1/2*80 is 40
40%*90
10%*90 is 9
40%*90 is 9*4 which is 36
so 1/2 of 80 is bigger