Multiplying positive and negative numbers

Difficulty Standard · Set m11qdt

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1
6×(-12)=
2
(-8)×(-14)=
3
(-18)×9=
4
(-21)×(-13)=
5
8×(-26)=
6
17×(-28)=
7
(-6)×(-28)=
8
(-3)×22=
9
(-11)×5=
10
9×(-14)=
11
13×(-25)=
12
(-18)×7=
13
(-12)×4=
14
7×(-25)=
15
(-12)×(-20)=
16
(-21)×(-30)=
17
(-29)×(-8)=
18
(-20)×28=
19
(-30)×(-5)=
20
8×(-22)=

What is in this set

The numbers in this set run from 2 to 30.
70% of them have exactly one negative.
30% 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 70% of the problems: the sign came out wrong: one negative and one positive give a negative.
Answers are a whole number.

Drawing 240 problems from this page produced 232 different ones, 97% — 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 7 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.