| Key | Number |
| Enter 2 | |
| Enter 4 | |
| Equals 2+4 | |
| Sum of last two numbers | |
| Sum of last two numbers | |
| Sum of last two numbers | |
| Sum of last two numbers | |
| Sum of last two numbers | |
| Sum of last two numbers | |
| Sum of last two numbers | |
| | Key | Number |
| Sum of last two numbers | |
| Sum of last two numbers | |
| Sum of last two numbers | |
| Sum of last two numbers | |
| Sum of last two numbers | |
| Sum of last two numbers | |
| Sum of last two numbers | |
| Sum of last two numbers | |
| Sum of last two numbers | |
| Sum of last two numbers | |
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