1 x 100 = 100
One times 100 is 100. Multiplying by one leaves a number exactly as it was, which is why 1 is called the identity for multiplication. The answer never changes.
1 × 100 = 100
Adding 1 to itself 100 times gives the same answer.
Why the answer is simply 100
One is the multiplicative identity. Any number multiplied by 1 comes back unchanged, so 1 x 100 = 100, and 100 x 1 = 100 as well. This is the only calculation in the set where the answer is also one of the two numbers you started with, which is why it looks like a trick question and is not one.
The mix-up worth naming
Plenty of people land here when they actually meant 1 percent of 100, which is 1, not 100. Percent means per hundred, so it divides by a hundred instead of multiplying by it. If a fraction of a hundred is what you need, 0.1 x 100 gives 10 and 0.5 x 100 gives 50.
About the number 100
100 is 10 squared, the square of the base we count in. It has exactly nine divisors: 1, 2, 4, 5, 10, 20, 25, 50 and 100. That divisibility is the reason percentages, cents and centimeters all settled on a hundred rather than some less cooperative number.
The next rungs up
The full directory sits at multiplication answers.