1 4 9 10y 7 8 July 8, 2019 16 32 64 128 1 4 9 10y 3 5y 7 8 1 4 9 10y 3 5y 7 8 simplified 1 4 9 10y − 3 5y 7 8 1 7/-4 9-1 9 1 7 × +4 9=10 1+9= 10
