Reflecting a point in the y-axis

Difficulty Standard · Set gohrbo

Give each new point as x, y.

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

1
Reflect (11, 9) in the y-axis.
2
Reflect (11, -3) in the y-axis.
3
Reflect (11, -1) in the y-axis.
4
Reflect (4, 1) in the y-axis.
5
Reflect (12, -10) in the y-axis.
6
Reflect (-6, 8) in the y-axis.
7
Reflect (-3, 9) in the y-axis.
8
Reflect (-9, 9) in the y-axis.
9
Reflect (-6, 11) in the y-axis.
10
Reflect (-2, 2) in the y-axis.
11
Reflect (-9, 10) in the y-axis.
12
Reflect (-5, 12) in the y-axis.
13
Reflect (-11, -9) in the y-axis.
14
Reflect (-6, -1) in the y-axis.
15
Reflect (4, 12) in the y-axis.
16
Reflect (3, -3) in the y-axis.
17
Reflect (-9, 8) in the y-axis.
18
Reflect (6, -7) in the y-axis.
19
Reflect (-2, 2) in the y-axis.
20
Reflect (-10, 11) in the y-axis.

What is in this set

The numbers in this set run from 1 to 12.
A careful solution takes 2 written steps on average.
The mistake this set invites most often, in 100% of the problems: a reflection in the y-axis leaves the y coordinate alone and changes the sign of the other one.
Answers are a short answer exactly as the problem asks for it.

Drawing 240 problems from this page produced 195 different ones, 81% — 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.