Ответ:

1. 40% = 0,4

2. 10:2/12:2=5/6

3. 8/21 менше,ніж 3/7. 3×3=9,7×3=21

9/21 > 8/21

4. 9 = 75%

25% = 9:3

25%=3

3×4=12 - 100%

5. 9/10+3/8 = 51/40

1 7/12 + 2 1/2 = 7+2=9=7/12+1/2=13/12=1 1/12

9+1=10

10+ 1/12 = 10 1/2