Finding the missing number in a proportion

Difficulty Standard · Set eeuem1

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1
25=?25— what is the missing number?
2
94=?12— what is the missing number?
3
36=?42— what is the missing number?
4
56=?48— what is the missing number?
5
57=?56— what is the missing number?
6
95=?35— what is the missing number?
7
66=?30— what is the missing number?
8
53=?9— what is the missing number?
9
26=?12— what is the missing number?
10
84=?20— what is the missing number?
11
54=?12— what is the missing number?
12
42=?8— what is the missing number?
13
35=?35— what is the missing number?
14
73=?18— what is the missing number?
15
34=?16— what is the missing number?
16
89=?45— what is the missing number?
17
63=?9— what is the missing number?
18
26=?48— what is the missing number?
19
76=?36— what is the missing number?
20
28=?32— what is the missing number?

What is in this set

The numbers in this set run from 2 to 72.
A careful solution takes 2 written steps on average.
The mistake this set invites most often, in 85% of the problems: the bottom grew by 24 and the same was added on top.
Answers are a whole number.

Drawing 240 problems from this page produced 180 different ones, 75% — so a sheet of 20 is a new sheet almost every time.

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.