3 1/3 · 4 1/5 + 4 2/10 · 5 2/3 + 3 1/3 · 2 4/5 + 2 8/10 · 5 2/3 =
=4 1/5 · (3 1/3 + 5 2/3) + 2 4/5 · (3 1/3 + 5 2/3) =
= (3 1/3 + 5 2/3) · (4 1/5 + 2 4/5) =
= 9 · 7 = 63
3 1/3 · 4 1/5 + 4 2/10 · 5 2/3 + 3 1/3 · 2 4/5 + 2 8/10 · 5 2/3 =
=4 1/5 · (3 1/3 + 5 2/3) + 2 4/5 · (3 1/3 + 5 2/3) =
= (3 1/3 + 5 2/3) · (4 1/5 + 2 4/5) =
= 9 · 7 = 63