STANDARDS FOR MATHEMATICAL CONTENT MCC.2.OA.1 Use addition and subtraction within 100 to solve one- and two-step word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using drawings and equations with a symbol for the unknown number to represent the problem.
MCC.2.NBT.5 Fluently add and subtract within 100 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction.
How can subtraction help us to know if we added correctly?
How can addition help us know if we subtracted correctly?
Math Appeal by Greg Tang or similar addition riddle story
GROUPING Small group
TASK DESCRIPTION, DEVELOPMENT, AND DISCUSSIONPart I
Gather students together on the meeting area. Read Math Appeal by Greg Tang or similar addition riddle story. Discuss addition pictures with class and have students answer riddles as you read the story.
Show students a picture from a magazine. Make sure the magazine picture offers several possible groups or combinations and would be interesting. Discuss the picture with the whole class. The children may want to ask questions that can be answered by the picture, but do not require an operation and can be found by counting. Possible examples:
There are 6 groups of 2 dogs pulling the sled. How many dogs are pulling the sled?
There are 23 mice in the picture. 15 are under the table. How many are on top of the table?
Give students a picture from a magazine or a coloring book. Try to make sure the pictures have several number combinations for two-digit numbers. Have students describe what they see in their picture and create number sentences to match their descriptions. Encourage students to check their answers using the inverse operations. As students are working on their number sentences, walk around and ask questions like:
What numbers do you see within your picture?
How can you use these numbers in an equation?
How are you describing your picture with number sentences?
How can you check your answer to see that it is correct?
Is there another number sentence you could write with those numbers?
Have students create a story problem to go along with one of the number sentences (equations) that they wrote for the picture. Let students share their story problems and pictures with the class. Allow other students to ask questions or make comments about the student’s work. See if students can come up with additional story problems for each picture.