Explain why 1/2 is not equivalent to 2/5

If you were to make the denominators equivalent, you'd see they aren't equivalent.

1/2=5/10

2/5=4/10

...Hope that helps

Onen way, is to know that
if a=b and c=d, then a/c=b/d, and thn (a/c)(d/b)=1

the real way would be to make denomenators the same

one way would be to firs assume they are equal then show it is false
1/2=2/5
times right sides by 5/5 and left by 2/2
5/10=4/10
times 10 both sides
5=4
flase

it is not equal