Odpowiedź:
1) a
3/4 × 4/5 = 3/5
b
4/15 × 5/12 = 1/9
c
7/9 × 7/11 = 49/99
2) a
5/6 × 1 1/5 = 5/6 × 6/5 = 1
b
1 2/3 × 3 4/5 = 5/3 × 19/ = 19/3 = 6 1/3
c
1 5/7 × 14/5 = 12/7 × 14/15 = 8/20 = 2/5
3) 3/4 - 2/3 = 9/12 - 8/12 = 1/12
3/4 = 75 dkg
75 : 3 = 25 dkg
2/3 = 2 × 25 dkg = 50 dkg czyli więcej niż 30 dkg .
