standard_description: Fluently add and subtract within 20 using mental strategies. (See standard 1.OA.6 for a list of mental strategies.) By end of Grade 2, know from memory all sums of two one-digit numbers.
problem_activity: Problem 1
Circles
$$A$$
and
$$C$$
are shown below.
[IMG]
Write an equation that describes each of the circles.
Problem 2
Write the equation of a circle whose diameter has endpoints of
$$(-8, 2)$$
and
$$ (2, 2)$$
.
Problem 3
Describe how you could prove that circle
$$A$$
is similar to circle
$$B$$
.
[IMG]


aligns: no