Finding the missing number in a proportion

Difficulty Stretch · Set 1lzx0x

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1
38=?16— what is the missing number?
2
96=?48— what is the missing number?
3
62=?38— what is the missing number?
4
54=?80— what is the missing number?
5
67=?140— what is the missing number?
6
23=?63— what is the missing number?
7
74=?28— what is the missing number?
8
96=?90— what is the missing number?
9
28=?176— what is the missing number?
10
78=?88— what is the missing number?
11
52=?28— what is the missing number?
12
66=?114— what is the missing number?
13
77=?133— what is the missing number?
14
99=?36— what is the missing number?
15
63=?24— what is the missing number?
16
93=?39— what is the missing number?
17
88=?96— what is the missing number?
18
64=?28— what is the missing number?
19
98=?80— what is the missing number?
20
96=?126— what is the missing number?

What is in this set

The numbers in this set run from 2 to 198.
A careful solution takes 2 written steps on average.
The mistake this set invites most often, in 86% of the problems: the bottom grew by 34 and the same was added on top.
Answers are a whole number.

Drawing 240 problems from this page produced 217 different ones, 90% — 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.