Question

Choose any four consecutive even numbers. (For example: 6, 8, 10, 12). Multiply the two middle numbers together. (e.g. 8 x 10 = 80) Multiply the first and last numbers. (e.g. 6 x 12 = 72) Now subtract your second answer from the first. (e.g. 80 - 72 = 8) Try it with your own numbers. Why is the answer always 8?

Answer 1

Explanation:

let the consecutive even numbers be 2n-2,2n,2n+2,2n+4 where n>0 and n is an integer.

2n(2n+2)-(2n-2)(2n+4)

=4n²+4n-(4n²+8n-4n-8)

=4n²+4n-4n²-8n+4n+8

=8