multiples of six

6, 12, 18, 24, 30, 36, 42, 48, 54, 60, 66, 72, 78, 84, 90, 96, 102, 108, 114, 120

What does it mean when it says "The sum of the digits is less than eight"?

"The sum of the digits is less than eight" means that when you add together all the individual digits of a number, the total sum is less than eight. For example, the number 245 would meet this criteria because 2 + 4 + 5 = 11, which is greater than eight.