Oblicz:
a) 1/2 - 2/5 =
2 i 11/12 - 4/9 =
9 i 5/9 - 2 i 4/5 =
4 i 2/11 - 2 i 2/3 =

b) 8/7 - 2/3 =
10 i 13/15 - 5/6 =
8 i 3/8 - 7 i 5/6 =
7 i 1/3 - 4 i 20/21 =

Proszę o rozpisanie!
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