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How many terminal zeroes will N have?

If a number ends in zero, the zeros are called terminal zeros. For example, 520,000 has four terminal zeroes, but 502,000 has just three terminal zeros. Let N equal the product of all counting numbers from 1 through 20.
N = 1×2×3×4× ... ×20
How many terminal zeroes will N have when it is written in standard form?

Terminal zeroes are obtained when multiplied by 10. So from numbers 1 to 20, we have two tens i.e; 10 and 20 => 2 zeroes
We have two 5s and two 2s i.e; 5,15 and 2,12 when multiplied will give two more zeroes.
N will have a total of 4 terminal zeros in the product.

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