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As Easy as 1,2,3

Age 11 to 14
Challenge Level Yellow star
  • Problem
  • Student Solutions

My calculator has 26 memories - one per letter of the alphabet. When I type a sequence of letters the calculator gives the product of all the numbers in the corresponding memories. I want to put numbers in the various stores so that when I type the word ONE it returns 1, and when I type the word TWO it returns 2, and when I type the word THREE it returns 3 and so on. How far can you get ? Is there an integer above which it is impossible to get ?

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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...

Sum Equals Product

The sum of the numbers 4 and 1 [1/3] is the same as the product of 4 and 1 [1/3]; that is to say 4 + 1 [1/3] = 4 � 1 [1/3]. What other numbers have the sum equal to the product and can this be so for any whole numbers?

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.

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The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to embed rich mathematical tasks into everyday classroom practice.

NRICH is part of the family of activities in the Millennium Mathematics Project.

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