The remainders by the last digit

Sesanyankena Charamena

Find the remainder when a number is divided by 9 by simply summing its digits repeatedly until a single digit remains. This is known as 'casting out nines' and gives the remainder instantly.

How It Works

1.Take any number and sum all its digits.
2.If the result has more than one digit, sum the digits again.
3.Repeat until you get a single digit.
4.That single digit is the remainder when the original number is divided by 9.
5.Special case: if the digit sum is 9, the remainder is 0 (divisible by 9).

Examples

1234 ÷ 9

Step 1 / 4

Find the remainder when 1234 is divided by 9. Start by summing the digits.

Number1234

Digits1, 2, 3, 4

Try It Yourself

7654 ÷ 9 → remainder?

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