Math Misconception Test

No, 9.11 is not greater than 9.9.

In fact, 9.9 is greater than 9.11.

Here’s the simplest way to see why:

1. Line up the numbers by the decimal point. You can add a zero to the end of 9.9 without changing its value to make the comparison easier.

     9 . 1 1
     9 . 9 0
   

2. Compare digit by digit, starting from the left.

   • The whole number part is the same (9).
   • Look at the first digit to the right of the decimal (the tenths place).
     • In 9.11, the tenths digit is 1.
     • In 9.90, the tenths digit is 9.

3. Since 9 is greater than 1, the number 9.9 is larger.

Think of it as money:

• $9.11 is nine dollars and eleven cents.
• $9.90 is nine dollars and ninety cents.

Ninety cents is clearly more than eleven cents.