# Subtract a One-Digit Number from a Two-Digit Number - within 20

To find the difference, we need to count back from the greater number.

17 – 9 = ?

Let’s start from 17 and count back 9:

17, 16, 15, 14, 13, 12, 11, 10, 9, 8.

Now,

17 – 9 = 8

So, the difference of 17 and 9 is **8**.

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### Help

The correct answer is

##### Remember :

The smallest number is the one that comes first while counting.

##### Solution :

To arrange the given numbers in order from smallest to greatest, find the smallest number among all the given numbers.

21,27,23

21 is the smallest number.