Answer :
18/20 because you can't add 5 and 4 so you make the denominator the same so you just multiply 5×4 and 4×5this will give you 8/20+10/20=18/20
a/b+c/b=(a+c)/b
make bottom number same
multiply by 1 or x/x where x=x
easy way is
if you had
a/b+c/d
multiply a/b by d/d and multiply c/d by b/b
2/5 times 4/4=8/20
2/4 times 5/5=10/20
add
8/20+10/20=(8+10)/20)=18/20=9/10
I should have simplified 2/4 to 1/2 first
make bottom number same
multiply by 1 or x/x where x=x
easy way is
if you had
a/b+c/d
multiply a/b by d/d and multiply c/d by b/b
2/5 times 4/4=8/20
2/4 times 5/5=10/20
add
8/20+10/20=(8+10)/20)=18/20=9/10
I should have simplified 2/4 to 1/2 first