вычислите 1) 1/7+4/7-3/14 2)1/5-2/15+1/30 3) 1/107/20-2/40 4)17/20-3/10-11/60 4) 3/20+7/100-3/40 6)9/40+3/4-19/20

Почему 1/7, если вы сокращаете на 7?

1/7+4/7-3/14=(ноз 14) 2+8+3/14=7/14=1/7 это первый пример

1) 1/7 +4/7 - 3/14 = 2/14 + 8/14 - 3/14 = 7/14 = 1/22) 1/5 - 2/15 + 1/30 = 6/30 - 4/30 +1/30 = 3/30 = 1/103) 1/10 + 7/20 - 2/40 = 4/40 + 14/40 - 2/40 = 16/40 = 4/104) 17/20 - 3/10 - 11/60 = 51/60 - 18/60 - 11/60 = 22/60 = 11/305) 3/20 + 7/100 - 3/40 = 6/40 + 7/100 - 3/40 = 3/40 + 7/100 = 300/4000 + 280/4000 = 580/4000 = 29/2006) 9/40 + 3/4 - 19/20 = 9/40 + 30/40 - 38/40 = 1/40