Which two whole numbers – without any zeros – multiply together to make 1 000 000?
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Brainteaser answer
A good way to tackle this question is by breaking down 1 000 000 into smaller numbers.
1 000 000 = 10 x 10 x 10 x 10 x 10 x 10
And since 10 = 2 x 5, we know that:
1 000 000 = 2 x 5 x 2 x 5 x 2 x 5 x 2 x 5 x 2 x 5 x 2 x 5
We can reorder these:
1 000 000 = 2 x 2 x 2 x 2 x 2 x 2 x 5 x 5 x 5 x 5 x 5 x 5
And start grouping them again:
1 000 000 = 64 x 5 x 5 x 5 x 5 x 5 x 5
1 000 000 = 64 x 15625
Do you have another way of tackling the problem? Pop it in the comments below!
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2 responses
To answer the problem for 10:
2 X 5
Just keep doubling one side and halving the other to still make 10.
4 X 2.5
8 X 1.25
16 X .625
32 X .3125
64 X .15625
If we changed the magnitude of .15625, might we get the numbers we need? Let’s try.
64 X 15,625 = 1,000,000 Yes!
Break it into 100s and then into 25 and 4
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