No matter how we permute the 3 digits 1,2 4 ,
none of the 6 three- digit numbers (124,142,214,241,412,421) is a multiple of 7.

Clearly, out of 84 possible triplets created by choosing distinct non-zero digits

there must be several like this, i.e. generating a 6-pack of three-digit numbers,

non divisible by 7.

1. List those triplets.

2. Similar question re:4 digits and divisibility by 23.