First I always gather the known information..
So we know you have 9/10 yards of fabric... and that you need 2/7 to make 1 pillow.
The way we can figure out how many you can make is by dividing 9/10 by 2/7....
3.15 is your answer but of course we cannot make 3.15 pillows so your answer should be rounded to 3 :)
You can make 3 pillows out of 9/10 yd of fabric
hope this helped ya