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Prompt Cards

These two group activities use mathematical reasoning - one is numerical, one geometric.

Consecutive Numbers

An investigation involving adding and subtracting sets of consecutive numbers. Lots to find out, lots to explore.

Exploring Wild & Wonderful Number Patterns

EWWNP means Exploring Wild and Wonderful Number Patterns Created by Yourself! Investigate what happens if we create number patterns using some simple rules.

Reverse Trick

Age 7 to 11
Challenge Level

Solution 1
From Jonathan at St. Andrew's Primary School, Cullompton:

My answer is 272727.
This is how I worked it out. If you take the first example and set it out like this: (9+) 12 = 21 I worked out that 21 - 12 = 9 and the same with 51 - 15 = 36 (second example).
Therefore 414141 - 141414 has to equal the secret number, which is 272727.

Solution 2
From Hang Hao who goes to Pei Hwa Presbyterian Primary School, Singapore:

The answer to this problem is 272727.
Reversing 141414 gives 414141.
The secret number add 141414 gives 414141.
Therefore the secret number is obtained by 414141-141414 = 272727.