Primary Standards:
MAFS.1.OA.3.6 Add and subtract within 20, demonstrating fluency for addition and subtraction within 10. Use strategies such as counting on; making a ten; decomposing a number leading to a ten; using the relationship between addition and subtraction; and creating equivalent but easier or known sums.
MAFS.1.OA.3.5 Relate counting to addition and subtraction (e.g., by counting on 2 to add 2)
MAFS.1.OA.2.3 Apply properties of operations as strategies to add and subtract. Example: If 8 + 3 = 11 is known, then 3 + 8 = 11 is also known. (Commutative property of addition)
Connecting Standards:
MAFS.1.OA.4.8 Determine the unknown whole number in an addition or subtraction equation relating 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 = ?.
Content Knowledge:
The make-ten strategy is great for addition. It helps students understand place value and the relationships between numbers. Ten-frames help students develop a good “mind picture” for the make-ten strategy because our place-value system is based on making groups of ten. These mind pictures help many kids to do mental math with ease. They are especially important for students who need additional support. To introduce the strategy, use a double ten-frame with counters to represent a number fact such as 9 + 4. Have students fill the first ten-frame with 9 counters and the second ten-frame with 4. Ask questions such as How many are in each ten-frame? How do you know we have 9 in the left? (It has 1 less than 10. I see a column of 5 and 4 more.) Then have kids slide one counter from the group of 4 to fill the ten-frame that had 9. Use language that links the first number fact (9 + 4) to the new number fact (10 + 3). “Nine and four is the same amount as ten and three.” Give students time to use concrete materials to move quantities around and build their mind pictures of how quantities can move from one group to another. (Origo Feb. 2020)
GCG 1: Learning Goal: As a Mathematician, I will be able to Count On/Count Back within 20
- Step 1: Represent counting on 0, 1, 2 within 20 using concrete tools, drawings and equations
- Step 2: Represent counting back 0, 1, 2 within 20 using concrete tools, drawings and equations
- Step 3: Use the Commutative Property to count on/count back 0, 1, 2
GCG 2: Learning Goal: As a Mathematician, I will be able to Doubles/Near Doubles within 20
- Step 1: Use concrete tools, drawings and equations to represent doubles within 20
- Step 2: Represent Doubles Plus One/Two using concrete tools, drawings and equations within 20
- Step 3: Represent Doubles Minus One/Two using concrete tools, drawings and equations within 20
- Step 4: Use Doubles and Near Doubles to solve word problems within 20
GCG 3: Learning Goal: As a Mathematician, I will be able to Make a Ten to Add on
- Step 1: Represent Making a Ten using concrete tools, drawings and equations
- Step 2: Direct model Make a Ten to add on using counters and a tens frame
- Step 3: Represent Making a Ten to add on using drawings and number lines
- Step 4: Represent Making a Ten to add on with equations
GCG 4: Learning Goal: As a Mathematician, I will be able to Subtract using Ten