12 1/15 - 8 2/3=
\(12 \frac {1} {15}+8 \frac {2} {3} = \frac {12 \times 15 +1+8 \times 15 + 2 \times 5}{15}= \frac {311}{15}\) = \(20 \frac {11}{15}\)
12 1/15 - 8 2/3 = 181/15 - 130/15 = 51/15 = 3 6/15 = 3 2/5
Sorry!
\(12 \frac {1} {15}-8 \frac {2} {3} = \frac {12 \times 15 +1-8 \times 15 - 2 \times 5}{15}= \frac {51}{15}\) = \(3 \frac {2}{5}\)
