Chinese Rem Theorem

This is an important idea in Math and today I exposed my year 7 and year 8 students to this beautiful theorem. To guess a number between 1 and 1000. All you need are these 7 numbers.

7,11,13, 715,364,924 and 1001. First you find the remainder of your unknown number with 7, 11 and 13 and then you multiply these remainder with the number 715,364 and 924 respectively. You add all the numbers and then divide by 1001 and viola you have your unknown number.