To find the total length of yarn used we need to calculate:

Length per student x Number of students

This is:

2/3 x 26

When multiplying a fraction with another number, or a fraction, just multiply the numerators (the part on the top) together and keep them on the top. Multiply the denominators (the part on the bottom) together and keep those together. For example if you had two fractions:

a/b x c/d

Then you would get:

(a x c) / (c x d)

So here, we have 2/3 x 26. Remember you can think of 26 as being 26/1! So we have:

(2 x 26) / (3 x 1)

= 52 / 3

This is 17 1/3 yards of yarn in total.

Hope this was helpful but do let me know if anything is unclear!

Apr 2nd, 2015

Whoops, typo in a part of the explanation. It should read:

...

a/b x c/d

Then you would get:

(a x c) / (b x d)

...

This is because a and c are the numerators (mutliply them together, keep them on the top) and b and d are the denominators (multiply together, keep them on the bottom).