Amy's math notebook weighs 1/2 pound her science notebook weighs 7/8 and her history notebook weighs 3/4 pound what are the weights in order from lightest to heaviest

You can turn the fractions into equal denominators by multiplying the top and bottom equally. So 1/2 is 4/8, 3/4 is 6/8, and so using this we know the order is 1/2,3/4, and 7/8.

Think of it as five or above give it a shove. change the 5 or above to the right to a zero and add one to the number on the left.