_____________________
|  _________________  |
| |                 | |
| | RETROFIT = £££  | |
| |_________________| |
|  ___ ___ ___   ___  |
| | 7 | 8 | 9 | | + | |
| |___|___|___| |___| |
| | 4 | 5 | 6 | | - | |
| |___|___|___| |___| |
| | 1 | 2 | 3 | | x | |
| |___|___|___| |___| |
| | . | 0 | = | | ÷ | |
| |___|___|___| |___| |
|_____________________|

RetrofitSavingsCalculator