You may also like
Adding All Nine
Make a set of numbers that use all the digits from 1 to 9, once and once only. Add them up. The result is divisible by 9. Add each of the digits in the new number. What is their sum? Now try some other possibilities for yourself!
Double Digit
Choose two digits and arrange them to make two double-digit numbers. Now add your double-digit numbers. Now add your single digit numbers. Divide your double-digit answer by your single-digit answer. Try lots of examples. What happens? Can you explain it?
Age 11 to 14 Challenge Level:
There are at least twelve solutions to the addition sum
| M | U | M | |
| + | D | A | D |
| -- | -- | -- | -- |
| K | I | D | S |
You have to replace the seven letters by seven numbers. How many solutions can you find? How many solutions are there?
Copyright © 1997 - 2020. University of Cambridge.
All rights reserved.
NRICH is part of the family of activities in the Millennium Mathematics Project.
NRICH is part of the family of activities in the Millennium Mathematics Project.