Thursday, December 31, 2009

How many 4-digit numbers are divisible by 2 or 5?

How many numbers from 1000 to 9999 are divisible by 2 or 5?





Is it 9 x 10 x 10 x 6 = 5400? Or something else?How many 4-digit numbers are divisible by 2 or 5?
its done like this . 9999 - 1000 = 8999





8999/5 = 1799.5





therefore we have 1799 numbers that are divisible by 2 or 5How many 4-digit numbers are divisible by 2 or 5?
First of all we have 4500 numbers divisible by 2. Then we have 1800 numbers divisible by 5, 900 of those are also divisible by 2 (and therefore 900 not divisible by 2). So, we have 5400 numbers divisible by 2 or 5 between 1000 and 9999.

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