standard_description: Add within 100, including adding a two-digit number and a one-digit number, and adding a two-digit number and a multiple of 10, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used. Understand that in adding two-digit numbers, one adds tens and tens, ones and ones; and sometimes it is necessary to compose a ten.
problem_activity: Problem 1
Four expressions are shown in the chart below. For each one, write all the ways to read the expressions that you can think of.
| **             $${x+2}$$            ** |                 $${x-2}$$                 |
|----------------------------------------|-------------------------------------------|
|                                        |                                           |
|                $${2x}$$                | **             $${x\div2}$$            ** |
|                                        |                                           |
Problem 2
Two tape diagrams are shown below. The shading indicates subtraction.
[IMG]
Statements a–h below can be used to describe either Diagram 1 or Diagram 2. Match each statement to one of the diagrams.
a.   The difference of
$$4$$
and
$$m$$
b.   The difference of
$$m$$
and
$$4$$
c.
$$4$$
less than
$$m$$
d.
$$m$$
less than
$$4$$
e.
$$4$$
less
$$m$$
f.
$$m$$
less
$$4$$
g.   Subtract
$$4$$
from
$$m$$
h.   Subtract
$$m$$
from
$$4$$
Problem 3
For each verbal statement, write the algebraic expression it describes.
a.   The sum of
$$e$$
and
$$f$$
subtracted from
$$g$$
b.
$$g$$
less than the sum of
$$e$$
and
$$f$$
c.
$$g$$
more than twice
$$f$$


aligns: no