This is an excellent practice for the solution of quadratic equations.
1*36=36 => (1,36)
2*18=36 => (2,18)
3*12=36 => (3,12)
4*9=36 => (4,9)
6*6=36 => (6,6)
9*4=36 => (9,4)
12*3=36 => (12,3)
18*2=36 => (18,2)
36*1=36 => (36,1)
We can see that the sum decreases until the two factors are close (or equal) and then increases again.
The pair of integers with a sum of 20 is therefore (2,18) or (18,2).
6/3 + 2/3 = (6 + 2)/3:
4 + 3/8 - (6 + 2)/3
6 + 2 = 8:
4 + 3/8 - 8/3
Put 4 + 3/8 - 8/3 over the common denominator 24. 4 + 3/8 - 8/3 = (24×4)/24 + (3×3)/24 + (8 (-8))/24:
(24×4)/24 + (3×3)/24 + (8 (-8))/24
24×4 = 96:
96/24 + (3×3)/24 + (8 (-8))/24
3×3 = 9:
96/24 + 9/24 + (8 (-8))/24
8 (-8) = -64:
96/24 + 9/24 + (-64)/24
96/24 + 9/24 - 64/24 = (96 + 9 - 64)/24:
(96 + 9 - 64)/24
| 1 |
| 9 | 6
+ | | 9
1 | 0 | 5:
(105 - 64)/24
| 0 | 10 |
| 1 | 0 | 5
- | | 6 | 4
| 0 | 4 | 1:
Answer: 41/24 or decimal 1.70833333.....
