Subtracting positive and negative numbers

Difficulty Starter · Set 2o5tij

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

1
(-12)−(-4)=
2
(-8)−5=
3
(-10)−(-12)=
4
(-3)−9=
5
2−(-7)=
6
11−(-10)=
7
(-3)−(-12)=
8
7−(-7)=
9
(-8)−9=
10
(-9)−11=
11
(-8)−(-9)=
12
(-3)−12=
13
(-5)−4=
14
(-3)−(-7)=
15
(-4)−(-2)=
16
(-2)−2=
17
(-6)−4=
18
(-8)−(-4)=
19
(-5)−6=
20
11−(-3)=

What is in this set

The numbers in this set run from 2 to 12.
65% of them have exactly one negative.
35% of them have a negative on both sides.
A careful solution takes 2 written steps on average.
The mistake this set invites most often, in 73% of the problems: taking away a negative was treated as taking away — subtracting a negative adds.
Answers are a whole number.

Drawing 240 problems from this page produced 176 different ones, 73% — 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.