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Here is a grid of four boxes:
|
|
|
|
You must choose four different digits from 1 - 9 and put one in each box. For example:
5 |
2 |
1 |
9 |
This gives four two-digit numbers:
52 (reading along the first row)
19 (reading along the first row)
51 (reading down the left-hand column)
29 (reading down the right-hand column)
In this case their sum is 151.
Try a few examples of your own.
Is there a quick way to tell if the total is going to be even or odd?
Your challenge is to find four different digits that give four two-digit numbers which add to a total of 100.
How many ways can you find of doing it?
You may be interested in the other problems in our Mastering Mathematics: Developing Generalising and Proof Feature.
This problem is adapted from Make 200 from 'Mathematical Challenges for Able Pupils Key Stages 1 and 2', published by DfES.