Explanation:
1. (2+4+1)/9 = 7/9
2. 2 1/3 + 2/3 = 2 + (1+2)/3 = 2 + 3/3 = 2+1 = 3
3. 1 1/5 + 2 3/5 = 1+2 + 1/5 + 3/5 = 3 + (1+3)/5 =
3 4/5
4. 5/6 + 2/10 + 1/5 = 5/6 + 1/5 + 1/5 = 5/6 + 2/5
= (5×5)/(6×5) + (2×6)/(5×6)
= 25/30 + 12/30
= (25+12)/30
= 37/30 = 1 7/30
5. 3 1/2 + 4 2/3
= 3+4 + 1/2 + 2/3
= 7 + (1×3)/(2×3) + (2×2)/(3×2)
= 7 + 3/6 + 4/6
= 7 + (3+4)/6 = 7 7/6 = 8 1/6
6. 9/13 - 5/13 = (9-5)/13 = 4/13
7. 7 6/8 - 5 2/8
= (7-5) + (6/8 - 2/8)
= 2 + 4/8
= 2 1/2
8. 2/3 - 3/7
= (2×7)/(3×7) - (3×3)/(7×3)
= 14/21 - 9/21 = (14-9)/21 = 5/21
9. 11 1/5 - 5 4/5
= 10 6/5 - 5 4/5
= (10-5) + (6/5 - 4/5)
= 5 + 2/5 = 5 2/5
10. 15 4/5 - 7 7/10
= (15-7) + (4/5 - 7/10)
= 8 + (4×2)/(5×2) - 7/10
= 8 + 8/10 - 7/10
= 8 + 1/10
= 8 1/10