standard_description: Compose and decompose numbers from 11 to 19 into ten ones and some further ones, e.g., by using objects or drawings, and record each composition or decomposition by a drawing or equation (e.g., 18 = 10 + 8); understand that these numbers are composed of ten ones and one, two, three, four, five, six, seven, eight, or nine ones.
problem_activity: Triangle
$${{{CDE}}}$$
underwent a transformation that created triangle
$${{{C'D'E'}}}$$
.
[IMG]
a.   Describe how triangle
$${{{CDE}}}$$
was transformed to become triangle
$${{{C'D'E'}}}$$
.
b.   What features stayed the same?
c.   What features changed?
d.   Is triangle
$${{{CDE}}}$$
congruent to triangle
$${{{C'D'E'}}}$$
? Explain how you know.


aligns: no