standard_description: Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
- The numbers from 11 to 19 are composed of a ten and one, two, three, four, five, six, seven, eight, or nine ones.
- The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
- 10 can be thought of as a bundle of ten ones — called a “ten.”
problem_activity: Task
Below is a picture of a triangle on a coordinate grid:
[IMG]
Draw the reflection of $\triangle ABC$ over the line $x = -2$. Label
the image of $A$ as $A^\prime$, the image of $B$ as  $B^\prime$ and
the image of $C$ as $C^\prime$.
Draw the reflection of $\triangle A^{\prime}B^{\prime}C^\prime$ over the line $x = 2$. Label
the image of $A^\prime $ as $A^{\prime \prime}$, the image of $B^\prime$ as  $B^{\prime \prime}$ and
the image of $C^\prime$ as $C^{\prime \prime}$.
What single rigid transformation of the plane will map $\triangle ABC$ to
$\triangle A^{\prime \prime}B^{\prime \prime}C^{\prime \prime}$?  Explain.


aligns: no