10, 20, 30, 40, 50, 60, 70, 80 & 90.
Find a two-digit number so that when the digits are added together the answer is one half of the answer you get when the 2 digits are multiplied together.
Find a two digit number, so that when the digits are added together the answer is one third of the answer when the 2 digits are multiplied together.
Using the digits 1, 2, 3 and 4, find the number of 10-digit sequences that can be written so that the difference between any two consecutive digits is 1.
Examples of such 10-digit sequences are ********** and **********.