Найдите значение выражения: а) 2/5 + 3/5 , б) 12/21 + 3/7, в) 9/10 - 4/25, г) 3/4 - 4/9, д) 3/4 + 2/3 - 1/6, е) 3/9 - 1/3 + 5/6.

а) 2/5 + 3/5 = 5/5 = 1

б) 12/21 + 3/7 = 12/21 + 9/21 = 21/21 = 1

в) 9/10 - 4/25 = 45/50 - 8/50 = 37/50

г) 3/4 - 4/9 = 27/36 - 24/36 = 3/36 = 1/13

д) 3/4 + 2/3 - 1/6 = 9/12 + 8/12 - 2/12 = 15/12 = 5/4 = 1 1/4

е) 3/9 - 1/3 + 5/6 = 6/18 - 6/18 + 15/18 = 15/18 = 5/6.

а) 2/5 + 3/5 ,=1

б) 12/21 + 3/7,=12/21+9/21=1

в) 9/10 - 4/25,=45/50-8/50=37/50

г) 3/4 - 4/9,=27/36-24/36=1/13

д) 3/4 + 2/3 - 1/6,=9/12+8/12-2/12=15/12=5/4=1 1/4

е) 3/9 - 1/3 + 5/6.=6/18-6/18+15/18=15/18=5/6