Putting a number through a rule

Difficulty Starter · Set 5y9qon

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1
A rule turns x into 2x + 4. What does it turn 4 into?
2
A rule turns x into 2x + 9. What does it turn 3 into?
3
A rule turns x into 2x + 1. What does it turn 4 into?
4
A rule turns x into 3x + 7. What does it turn 2 into?
5
A rule turns x into 2x + 2. What does it turn 2 into?
6
A rule turns x into 3x + 2. What does it turn 3 into?
7
A rule turns x into 2x + 6. What does it turn 4 into?
8
A rule turns x into 3x + 2. What does it turn 3 into?
9
A rule turns x into 2x + 4. What does it turn 2 into?
10
A rule turns x into 2x + 8. What does it turn 3 into?
11
A rule turns x into 3x + 6. What does it turn 3 into?
12
A rule turns x into 3x + 3. What does it turn 3 into?
13
A rule turns x into 3x + 4. What does it turn 2 into?
14
A rule turns x into 2x + 8. What does it turn 2 into?
15
A rule turns x into 2x + 7. What does it turn 2 into?
16
A rule turns x into 2x + 7. What does it turn 2 into?
17
A rule turns x into 3x + 7. What does it turn 3 into?
18
A rule turns x into 3x + 8. What does it turn 2 into?
19
A rule turns x into 3x + 4. What does it turn 2 into?
20
A rule turns x into 3x + 2. What does it turn 4 into?

What is in this set

The numbers in this set run from 1 to 9.
A careful solution takes 2 written steps on average.
The mistake this set invites most often, in 100% of the problems: the 1 was added before the multiplication.
Answers are a whole number.

Drawing 240 problems from this page produced 54 different ones, 23% — 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.