There is only one problem in recursive equation calculation, which needs to be solved in the process 5 out of 17 minus 4 out of 51 plus 2 out of 3

There is only one problem in recursive equation calculation, which needs to be solved in the process 5 out of 17 minus 4 out of 51 plus 2 out of 3

5 out of 17 minus 4 out of 51 plus 2 out of 3
=15/51-4/51+34/51
=45/51
=15/17
To adopt the first correct answer is to respect the labor of the respondents. I wish you progress!

(Volume 2 of grade 5) use recursive equation to calculate. Those who can use simple calculation should be simplified. 2.37-0.85-1.15104 * 2.5, 3.76 * 0.1/
The equation: 6.7 + x = 2.9 * 4.5, x-0.85x = 4.5, 5x-2.3 * 4 = 5,

2.37-0.85-1.15
=2.37-（0.85+1.15）
=2.37-2
=0.37

Four simple calculations
1. 1989×1999-1988×2000
2. 1/15+1/35+1/63+1/99+1/143+1/195
3. 4/3-7/12+9/20-11/30+13/42-15/56
4. 2/2×4+2/4×6+2/6×8+… +2/98×100

1.1989×1999-1988×2000=(1988+1)×1999-1988×2000=1988×1999+1999-1988×2000=1999-1988×(2000-1999)=1999-1988=12.1/15+1/35+1/63+1/99+1/143+1/195=1/2(1/3-1/5)+1/2(1/5-1/7)+1/2(1/7-1/9)+1/2(1/9-1/11)+1/...