There is a seven-digit number that is the product of six consecutive even numbers. The last six digits of the number are 290240.
What is the number?
There are two ways to solve this: one is brute force, multiplying six numbers together until you get the answer; the other is far more elegant, and requires no multiplication at all!
See if you can solve it the elegant way.
Here is the elegant way . . .
In any sequence of six consecutive even numbers two will be multiples of three. Multiplying two multiples of three together will result in a multiple of nine. The sum of the digits in a multiple of nine will be a multiple of nine, so the seven digits in this number must add up to a multiple of nine.
2 + 9 + 0 + 2 + 4 + 0 = 17, so the first digit must be 1 making a sum of 18.
1290240 = 6 x 8 x 10 x 12 x 14 x 16, which you could discover by multiplying sequences until you find the correct one