231 5 | × | 7 20 | + | 231 5 | × | 7 20 | a | = | 12243 500 |
| Left side of the equation = | 1617 100 | + | 1617 100 | a |
1617 100 | + | 1617 100 | a | = | 12243 500 |
1617 100 | a | = | 12243 500 | − | 1617 100 |
1617 100 | a | = | 2079 250 |
| a | = | 2079 250 | ÷ | 1617 100 |
| = | 2079 250 | × | 100 1617 |
| = | 9 5 | × | 2 7 |
| a | = | 18 35 |
| a | = | 0.514286 |