To solve this expression, we need to follow the order of operations, which is commonly known as PEMDAS (Parentheses, Exponents, Multiplication and Division, Addition and Subtraction).

1. First, we need to solve any operations inside parentheses, but there are none in this expression.

2. Next, we evaluate any exponents. In this case, we have 9² and 4².

9² = 9 * 9 = 81
4² = 4 * 4 = 16

So, the expression becomes: 1 + 1 × 81 : 16 - 7

3. Now, we perform any multiplication and division from left to right.

1 × 81 = 81

The expression becomes: 1 + 81 : 16 - 7

4. Finally, we perform any addition and subtraction from left to right.

81 : 16 = 5.0625 (division)

1 + 5.0625 - 7 = -0.9375 (addition and subtraction)

Therefore, the final result is -0.9375.