If you count them 2 by 2, one remains.
If you count them 3 by 3, 2 remain.
If you count them 4 by 4, 3 remain.
If you count them 5 by 5, 4 remain.
If you count them 6 by 6, 5 remain.
If you count them 7 by 7, none remain.
Find out the total number of mangoes in the basket.