You may also like
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?
Six Is the Sum
What do the digits in the number fifteen add up to? How many other numbers have digits with the same total but no zeros?
Age 7 to 14
Challenge Level
Sum-sum
Score = 42 + 16 = 58
With 1-8, the maximum score is more than 130 points
Take-take
Score = 55 - 35 = 20
With 1-8, the maximum score is more than 55 points
Take-sum
Score = 42 - 16 = 26
With 1-8, the maximum score is more than 70 points
Sum-take
Score = 12 + 24 = 36
With 1-8, the maximum score is more than 70 points
Copyright © 1997 - 2023. 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.