10. First find the common denominator for 7/8 and 9/10. I personally chose 35/40 and 36/40. Add the two fractions up to get a irregular fraction, which is 71/40. To then get a regular fraction, subtract 40 from 71 (which leaves you with a 1 in the ones place), then take the remaining number and put it like this: 1 31/40
A fact family is basically just different equations with the same numbers getting the same/different numbers as answers you might say... this will make more sense: 5x8=40 8x5=40 40/8=5 40/5=8
