1. The question "why is it =1" is unclear without context, but a common reason an expression equals 1 is due to properties of numbers or algebraic simplifications. 2. For example, if you have a fraction where numerator and denominator are the same, such as $$\frac{a}{a}$$, it equals 1 because any nonzero number divided by itself is 1. 3. Another example is the identity property of multiplication: multiplying by 1 leaves a number unchanged, so expressions like $$x \times 1 = x$$. 4. If you provide the exact expression or equation, I can explain why it equals 1 in that specific case.