Listing every factor of a number

Difficulty Starter · Set gjsb68

Fill in what you can and press Check. Nothing you type is sent anywhere.

1
List every factor of 34, smallest first, separated by commas.
2
List every factor of 16, smallest first, separated by commas.
3
List every factor of 39, smallest first, separated by commas.
4
List every factor of 37, smallest first, separated by commas.
5
List every factor of 22, smallest first, separated by commas.
6
List every factor of 35, smallest first, separated by commas.
7
List every factor of 30, smallest first, separated by commas.
8
List every factor of 35, smallest first, separated by commas.
9
List every factor of 14, smallest first, separated by commas.
10
List every factor of 18, smallest first, separated by commas.
11
List every factor of 31, smallest first, separated by commas.
12
List every factor of 34, smallest first, separated by commas.
13
List every factor of 16, smallest first, separated by commas.
14
List every factor of 23, smallest first, separated by commas.
15
List every factor of 24, smallest first, separated by commas.
16
List every factor of 30, smallest first, separated by commas.
17
List every factor of 31, smallest first, separated by commas.
18
List every factor of 25, smallest first, separated by commas.
19
List every factor of 22, smallest first, separated by commas.
20
List every factor of 30, smallest first, separated by commas.

What is in this set

The numbers in this set run from 12 to 40.
64% of them have seven factors or fewer.
20% of them are prime.
A careful solution takes 5.4 written steps on average.
The mistake this set invites most often, in 80% of the problems: a number is always a factor of itself, and 1 is a factor of everything — both belong in the list.
Answers are a short answer exactly as the problem asks for it.

Drawing 240 problems from this page produced 29 different ones, 12% — so a sheet of 20 will come back to a problem you have seen — there are only so many sensible ones of this kind.

The same skill, harder or easier

We would put this in front of a grade 4 class. That is our judgement, not a standard, and it is printed here so you can disagree with it. Everything else we put in that year.