126. 7x18 = 126. Then try to factor it down to find another solution. Another tactic is do multiples of 18 to find the first one divisible by 7. 18 isn't divisible by 7 36 isn't divisible by 7 54 isn't divisible by 7 72 isn't divisible by 7 90 isn't divisible by 7 108 isn't divisible by 7 126 is divisible by 7.