The names of numbers from 11 to 99 make little sense in the English language. The word “thirty” masks the pattern of the numbers. It also verbally masks place value, which is very evident in the names for the hundreds, thousands, and beyond.
We say 3 million, 3 thousand, 3 hundred; why not say 3-ten?
For a short time, the children will use the math way for number naming. Once they see the patterns and understand place value, they will link the math way of saying the numbers and traditional words.