Explanation:
Since you have 7/8 of a yard of fabric and 2/7 needed you would take the 7/8 and divide by 2/7
7/8 / 2/7
Since these are fractions you would take the second number and turn in into its reciprocal
7/8 x 7/2
49/16
3 1/16
You can make 3 full shirts