A Number Theory problem

Multiply the unit digits of each number. If suppose the result is an 2 digit number, check the unit digit of that number.This will be the unit digit of the above product This is true for any 2 natural numbers.Unit digits here are 4 and 3.4*3 = 12. Unit digit is thus 2.

The desired units digit in the problem is the units digit of the product of the units digit of each factor, we have $4 \times 3 = 12$ . So the desired units digit is $2$ .