1. Vasya can get the number 100 using ten sevens, parentheses, and arithmetic operation signs: $100=(77: 7-7: 7) \cdot(77: 7-7: 7)$. Improve his result: use fewer sevens and get the number 100. (It is sufficient to provide one example).
Solution. For example: 1) $100=777: 7-77: 7$, 2) $100=7 \cdot 7+7 \cdot 7+7: 7+7: 7$. There are $u$ other solutions.