Maria and jane bought a whole pizza pie. marie ate 1/5 of the pie and jane ate 1/4 of the pie. write a number sentence to find out how much is left and solve it

Eleven Twentieths of the pie are left, so that's 11/20

Method to solve;

Since its given a 1/4 and a 1/5 it's easiest to convert these to twentieths (the lowest common multiple of 4 and 5)

So 1/4 = 5/20

1/5 = 4/20

How much is eaten = 5/20 + 4/20 = 9/20

How much remains = Total (20/20) - How much eaten (9/20) = 11/20