The pronunciation of numbers in English often follows specific patterns that can seem inconsistent at first. The number 115 is pronounced "one fifteen" primarily because of the way we break down and group numbers.
When we read whole numbers, we tend to use the "tens" place value when it’s a two-digit number. In this case, "fifteen" corresponds to the digits "10" and "5". Thus, 115 is pronounced as "one" (the hundreds place) followed by