- #1
Animuo
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Homework Statement
How many zeroes are at the end of (45^8)(88^5), don't use a calculator.
Homework Equations
Using the unique factorization of integers theorem, you can break any integer down into the product of prime integers.
The Attempt at a Solution
So I broke it down
(45^8) = (3 * 3 * 5) ^ 8
(88^5) = (2 * 2 * 2 * 11) ^ 5
If you put it back together as separate factors you get something like this
(3^16) * (5^8) * (2^15) * (11^5)
now my thinking is that you can find the number of zeroes by figuring out how many factors of 10 (which equals 2 * 5) you can make.
You can make 8 factors of 10 so it looks like
(3 ^ 16) * (2 ^ 7) * (11 ^ 5) * (10 ^ 8)
And from this I assume that there would be 8 zeroes at the end, however if you check it with a calculator you get a different answer..
(45^8) * (88^5) = 8.87387835 × 10^22
Anyone care to explain where my thinking is wrong..?