Finding the missing number in a proportion

Difficulty Starter · Set ky0m8f

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

1
88=?24— what is the missing number?
2
94=?8— what is the missing number?
3
38=?16— what is the missing number?
4
68=?16— what is the missing number?
5
57=?21— what is the missing number?
6
89=?18— what is the missing number?
7
35=?15— what is the missing number?
8
33=?6— what is the missing number?
9
68=?16— what is the missing number?
10
25=?10— what is the missing number?
11
55=?15— what is the missing number?
12
62=?4— what is the missing number?
13
48=?24— what is the missing number?
14
48=?24— what is the missing number?
15
43=?6— what is the missing number?
16
86=?18— what is the missing number?
17
96=?12— what is the missing number?
18
36=?12— what is the missing number?
19
84=?8— what is the missing number?
20
64=?12— what is the missing number?

What is in this set

The numbers in this set run from 2 to 27.
A careful solution takes 2 written steps on average.
The mistake this set invites most often, in 90% of the problems: the bottom grew by 18 and the same was added on top.
Answers are a whole number.

Drawing 240 problems from this page produced 105 different ones, 44% — 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 6 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.