1.12/35

2.1/4
3.17/24
4.6.513
5.1/10
6.1/6
7.15
8.1 9/10
9.1/6
10.- 5/8
11.-2/3
12.6 1/12
13.37/100
14.16
15.7/4
16.20
17.3 yards
18.16 1/6
19.16 7/8
20.13

To solve these mathematical expressions, we'll need to perform some operations depending on the type of expression. I'll go through each problem step by step and explain the process.

1. 12 / 35:
To divide, we simply divide the first number (12) by the second number (35). The result is 0.34285714285714286.

2. 1 / 4:
Again, dividing the first number (1) by the second number (4) will give us the result. The result is 0.25.

3. 17 / 24:
Divide the first number (17) by the second number (24). The result is approximately 0.7083333333333333.

4. 6.513:
Since this expression is just a single number, there are no operations to perform. The result is simply 6.513.

5. 1 / 10:
Divide 1 by 10. The result is 0.1.

6. 1 / 6:
Divide 1 by 6. The result is approximately 0.16666666666666666.

7. 15:
This is a whole number, so there are no operations to perform. The result is simply 15.

8. 1 9/10:
This is a mixed number. We need to convert it to an improper fraction before performing any operations. To do that, we multiply the whole number (1) by the denominator of the fraction (10), and add the numerator (9) to get the new numerator. So, 1 9/10 is equal to (1 * 10 + 9)/10 = 19/10. The result is 1.9.

9. 1 / 6:
Divide 1 by 6. The result is approximately 0.16666666666666666.

10. - 5/8:
This is a negative fraction. To solve it, we subtract the numerator (-5) from 0 and keep the denominator (8) the same. The result is -5/8.

11. -2/3:
Same as the previous problem, this is a negative fraction. The result is -2/3.

12. 6 1/12:
This is a mixed number. To solve it, we convert it to an improper fraction. Multiply the whole number (6) by the denominator of the fraction (12) and add the numerator (1) to get the new numerator. So, 6 1/12 is equal to (6 * 12 + 1)/12 = 73/12. The result is approximately 6.083333333333333.

13. 37/100:
This is a regular fraction. The result is 37/100.

14. 16:
This is a whole number. The result is simply 16.

15. 7 / 4:
Divide 7 by 4. The result is 1.75.

16. 20:
This is a whole number. The result is simply 20.

17. 3 yards:
This is a unit of measurement, there are no operations we can perform. The result is simply 3 yards.

18. 16 1/6:
This is a mixed number. To solve it, we convert it to an improper fraction. Multiply the whole number (16) by the denominator of the fraction (6) and add the numerator (1) to get the new numerator. So, 16 1/6 is equal to (16 * 6 + 1)/6 = 97/6. The result is approximately 16.166666666666668.

19. 16 7/8:
This is a mixed number. To solve it, we convert it to an improper fraction. Multiply the whole number (16) by the denominator of the fraction (8) and add the numerator (7) to get the new numerator. So, 16 7/8 is equal to (16 * 8 + 7)/8 = 135/8. The result is approximately 16.875.

20. 13:
This is a whole number. The result is simply 13.