**Represent and solve problems involving addition and subtraction **

**1.OA.A.2 ****Solve word problems that call for addition of three whole numbers whose sum is less than or equal to 20, e.g. by using objects, drawings, and equations with a symbol for the unknown number to represent the problem.**

Three Addends Word Problems

Three Addends Problem Cards (all addends unknown)

**Understand and apply properties of operations and the relationship between addition and subtraction****1.OA.B.3** Apply properties of operations as strategies to add and subtract. Examples: If 8+3=11 is known, then 3+8=11 is also known (Commutative property of addition). To add 2+6+4, the second two numbers can be added to make a ten, so 2+6+4=2+10=12 (Associative property of addition).**Sample Activities:****Turn Around Trains****Turn Around Dominoes****Also included in**** 1st Grade Math Centers:**

Domino Fact Families**Three Addends**

Subtract from 10

Think Addition for Subtraction

Show One More

Show One Less

Show One More/One Less

Count On One (v. 2)

Count On Two (v. 1)

Count On Three (v. 1)

Doubles Cover Up (v. 2)

Find Ten

Making Ten (v. 1)

Four in a Row Subtraction

Part Part Whole Cards

Count On Cover Up (within 10)

Doubles Cover Up (v. 1)

Doubles Towers

Doubles Path

Doubles Concentration

Cuisenaire Doubles

Make 10 with Cuisenaire Rods

Make Ten on the Ten Frame

Towers of Ten

Making Ten (v. 3)

Sums of Ten

Doubles Plus One Towers

The Difference Game (v. 1-3)

**Work with addition and subtraction equations****1.OA.D.7 **Understand the meaning of the equal sign, and determine if equations involving addition and subtraction are true or false. For example, which of the following equations are true and which are false? 6=6, 7=8-1, 5+2=2+5 , 4+1=5+2**Sample Activities:**

True or False?**Also included in 1st Grade Math Centers:**

Equal Sums**1.OA.D.8** Determine the unknown whole number in an addition or subtraction equation relating to three whole numbers. For example, determine the unknown number that makes the equation true in each of the equations 8+ ? =11, 5 = □ – 3, 6+6 = □**Sample Activities:**

Find the Missing Number

**Extend the counting sequence**

**Understand place value****1.NBT.B.2** Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:

a. 10 can be thought of as a bundle of ten ones – called a “ten.”

b. The numbers from 11 to 19 are composed of a ten and one, two, three, four, five, six, seven, eight, or nine ones.

c. 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).**Sample Activities:**

Tens and Ones with Snap Cubes**Build a Train **

My Double Ten-Frame Riddle

Comparing Two Digit Numbers

Scoop It

Ten Frame Compare

Greater Than 50

Who Has the Greater Sum? (v. 1)

**Use place value understanding and properties of operations to add and subtract****1.NBT.C.4 **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.**Sample Activities:****Sums of 90 ****Subtract 10 on the Number Line** **Lucky Six**

Adding Tens to a 2-Digit Number

Add Ten on the Number Line

What Number is ...?

Ten More

Race Around -10 (v.1)

Subtract Ten

Subtract Multiples of Ten