Maya is packing her backpack for hike in one pocket she puts in 1/4 pound bag of trail mix a water bottle weighing 2 1/5 pounds in a flashlight weighing 1/4 lb how much weight did these three items add to her backpack

This problem is simply asking us to add the weights which are presented as fractions. You can easily get the answer if you input them directly in a calculator. But I think the challenge here is to manually add fractions.

Let's add the two 1/4 lb weights because it is easier for they have a common denominator. Just simply add the numerators.

1/4 + 1/4 = 2/4

Then, add with this the fraction part of 2 1/5.

2/4 + 1/5 = ?
The least common denominator is 4*5 = 20. Then divide 20 with each denominator and multiply to their respective numerator.

2/4 + 1/5 = [(20/4 * 2) + (20/5 *1)]/20 = 14/20

14/20 is simplified to 7/10. Then add the whole number 2. Therefore, the sum of all weights is 2 7/10 pounds.