Missing digits

Hello, and welcome to Myriora Maths! Some of the digits in this sum have gone missing. Can you find them? Here's how to crack it, one column at a time.

Always start with the ones. Seven plus something ends in three. Seven plus six is thirteen, so the missing digit is six. And we carry one ten.

Now the tens. Something plus five, plus the carried one, ends in two. So something plus six ends in two. Six plus six is twelve: so it's six, and we carry one again.

Then the hundreds. Four plus something, plus the carried one, makes eight. So four plus something is seven, and the missing digit is three.

Always check by doing the whole sum. Four hundred and sixty-seven plus three hundred and fifty-six is eight hundred and twenty-three. It works!

It works for times too. Thirty-something, times seven, is two hundred and sixty-six. Start with the ones: something times seven ends in six. Eight sevens are fifty-six! So it's thirty-eight. Check: thirty-eight times seven is two hundred and sixty-six.

A common mistake is forgetting the carry. In the tens column, some people think something plus five makes twelve, and say seven. But there's a carried one from the ones column! So it's six plus five plus one.

Your turn! Find the missing digits in this sum. You've got twenty seconds, or pause the video if you need more time. Go!

Time's up! Ones: eight plus seven is fifteen, so the missing digit is seven, and carry one. Tens: six plus four plus one is eleven, so it's six, and carry one. Hundreds: three plus two plus one is six. It works! Three hundred and sixty-eight, plus two hundred and forty-seven, is six hundred and fifteen.

Quick review. Start with the ones column. Think: what ends in the right digit? Don't forget the carries. And always check the whole sum at the end. See you next time!