21/20 - 3/8 - 1/5 = 42/40 - 15/40 - 8/40=19/40
21/20-3/8-1/5=42-15-8 /40=19/40
1/5+1/6=6+5/30=11/30
ответ:11/30
21/20 - 3/8 - 1/5 = 42/40 - 15/40 - 8/40=19/40
21/20-3/8-1/5=42-15-8 /40=19/40
1/5+1/6=6+5/30=11/30
ответ:11/30