standard_description: Add and subtract within 20, demonstrating fluency for addition and subtraction within 10. Use strategies such as counting on; making ten (e.g., 8 + 6 = 8 + 2 + 4 = 10 + 4 = 14); decomposing a number leading to a ten (e.g., 13 – 4 = 13 – 3 – 1 = 10 – 1 = 9); using the relationship between addition and subtraction (e.g., knowing that 8 + 4 = 12, one knows 12 – 8 = 4); and creating equivalent but easier or known sums (e.g., adding 6 + 7 by creating the known equivalent 6 + 6 + 1 = 12 + 1 = 13).
problem_activity: Problem 1
Explain how you know the expressions in Column A are equivalent to the expressions in Column B.
| **           Column A          ** | **           Column B          ** |
|-----------------------------------|-----------------------------------|
|           $${-3(x+4)}$$           |           $${-3x-12}$$            |
|           $${(4+x)+3}$$           |           $${x+(4+3)}$$           |
|           $${(x+4)-3}$$           |          $${-3+(x+4)}$$           |
Problem 2
Explain the properties of operations that were used to transform
$${a(x-y)}$$
to the equivalent expression,
$${-(ay-ax)}$$
.
Problem 3
If the expression
$${\frac{x}{2} + \frac{3}{4}}$$
is multiplied by
$$4$$
, the expression
$${{2x+3}}$$
results.
Is
$${{2x+3}}$$
an equivalent expression to
$${\frac{x}{2} + \frac{3}{4}}$$
?


aligns: no