Subtracting positive and negative numbers

Difficulty Stretch · Set h4oq9p

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1
(-70)−(-89)=
2
(-69)−(-34)=
3
29−(-20)=
4
45−(-96)=
5
(-6)−(-6)=
6
(-46)−77=
7
(-62)−78=
8
(-22)−84=
9
29−(-82)=
10
(-33)−(-72)=
11
(-26)−32=
12
80−(-21)=
13
9−(-99)=
14
73−(-48)=
15
34−(-72)=
16
(-79)−47=
17
28−(-39)=
18
96−(-75)=
19
4−(-66)=
20
94−(-9)=

What is in this set

The numbers in this set run from 2 to 99.
74% of them have exactly one negative.
26% 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 66% 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 239 different ones, 100% — 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.