Đáp án:
1:
a)7/5 + 4/7 - 9/10 = 49/35 + 20/35 -9/10 = 69/35 – 9/10 = 690/350 – 315/350 = 375/350 = 75/70 = 15/14
b)2 + 3/4 x 8/5 = 2 + 24/20 = 40/20 +24/20 = 64/20 = 32/10 = 16/5
a) 1/2 + 3/4 = 2/4 + 3/4 = 5/4
b)2 1/3 – 4/5 = 5/3 – 4/5 = 25/15 – 12/15 = 13/15
c) 5/4 : 2/3 = 5/4 x 3/2 = 15/8
d) 9/10 x 5/6 = 45/60 = ¾
2:
a)3/5 – X = 3/8 b)12825 : 45 – 45 x 3
X = 3/5 – 3/8 = 285 - 135
X = 9/40 = 150
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