Question

Oblicz:1/2 + 3/4
2/3 - 1/9
1/4 + 3/5
5/7 - 2/9

Answer 1

1/2 + 3/4 = 2/4 +3/4 = 5/4
2/3 - 1/9 = 6/9 - 1/9 = 5/9
1/4 + 3/5= 5/20 + 12/20= 17/20
5/7 - 2/9= 45/63 - 14/63= 31/63

Answer 2

½ + ¾ = 2/4 + 3/4 = 5/4 =1¼
⅔ - 1/9 = 6/9 - 1/9 = 5/9
1/4 + 3/5 = 5/20 + 12/20 = 17/20
5/7 - 2/9 = 45/63 - 14/63 = 31/63

Answer 3

1/2+3/4=1*2,2*2=2/4=3/4=5/4
2/3-1/9=2*9,3*9,1*3,9*3=18/27-3/27=15/27
1/4+3/5=1*5,4*5,3*4,5*4=5/20+12/20=17/20
5/7-2/9=5*9,7*9,2*7,9*7=45/63-14/63=31/63