We want to start by making both fractions have the same denominator. An easy way to do this is by multiplying the denominators by each other because they are such small numbers.
So, we multiply 31/3 by 4 to get 124/12
and we multiply 1/4 by 3 to get 3/12
Now we subtract the amount lost from the original amount
124/12 - 3/12 = 121/12
So, 121/12 tons of sand were delivered.
