Main Challenge
1,3
3x10=30
1x6=6
Total=36
3,1
1x10=10
3x6=18
Total=28
2,4
2x10=20
4x6=24
Total=44
4,2
4x10=40
2x6=12
Total=54
3,5
3x10=30
5x6=30
Total=60
5,3
5x10=50
3x6=18
Total=68
4,6
4x10=40
6x6=36
Total=76
6,4
6x10=60
4x6=24
Total=84
If you do the smallest number times by ten first and then switch it over the total goes up by eight each time. (Only if you do it systematically.) With each set of numbers there is a difference of two between them. There is six dice for one number and ten for another. So the difference between six and ten is four. Because there is four more numbers for one set of dice than the other and the difference between the two numbers on the dice is two. So you need to multiply four by two to equal eight. That is why eight is the difference between each total, of pairs of numbers.
Taking it further
It is always true if you have the difference of two between each number and ten of one number and six of another. (As we showed above.)
Whatever difference you have between the two numbers you need to times it by four because there is four more numbers for one set of dice than the other. Whatever number you times by four is the difference between the totals of the pairs of numbers.