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Tweedle Dum and Tweedle Dee
Two brothers were left some money, amounting to an exact number of pounds, to divide between them. DEE undertook the division. "But your heap is larger than mine!" cried DUM...
Special Sums and Products
Find some examples of pairs of numbers such that their sum is a factor of their product. eg. 4 + 12 = 16 and 4 × 12 = 48 and 16 is a factor of 48.
As Easy as 1,2,3
When I type a sequence of letters my calculator gives the product of all the numbers in the corresponding memories. What numbers should I store so that when I type 'ONE' it returns 1, and when I type 'TWO' it returns 2, and so on.
Age 11 to 14
Challenge Level
I have been practising arithmetic with fractions.
I worked out $4 + 1 \frac{1}{3}$ but then realised that I had misread the question!
I was supposed to work out $4 \times 1 \frac{1}{3}$
When I worked out the multiplication, I was surprised to find I got the same answer to both calculations!
Can you find other examples of calculations where replacing the multiplication sign by an addition sign does not alter the result of the calculation?
NRICH is part of the family of activities in the Millennium Mathematics Project.