This lesson asks students to figure out where the missing part is in a story problem and then represent that unknown with a symbol. This is aligned to 1.OA.1 and 1.OA.D8-both standards specifically ask students to work with unknowns in all positions. It also ask students to show that number is unknown by using a symbol-this is early algebra! This is also aligned to MP2, Reason abtractly and quantitatively. Students have to decontextualize the story and represent it only with numbers and symbols. Then they have to use a symbol to represent the unknown quantity.
I'll read students the text, See How They Grow. This is an informational text available for free on Wegivebooks.org (free login required). It is about the life cycle of a chicken. The Common Core shift includes using informational text in the classroom. This text gets kids interested in the concept of life cycles, which will also get them invested in solving today's problems.
Your thinking job today is: Which number sentence matches this story? How am I sure?
On Monday, 13 chicks hatched in the chicken coop. On Tuesday, some more chicks hatched. Now there are 16 chicks. How many chicks hatches on Tuesday?
Partner talk: Retell what happened first, next and last to your partner.
I have 3 equations hiding here.
I need your help determining which equation matches this story. All 3 quations have the same numbers in them, so we can't just look at the numbers. We have to think about which one matches what happened first, next and last.
Think Aloud for the first one: Does 13 + 16 match? Hmmm...13 and 16 more. Does that match? I had 13 chicks and then I got 16 more...no that isn't what happened. I need to X out this number sentence because it doesn't match what happened NEXT. It starts with 13 but I didn't get 16 more.
Partner talk: 16 -13: Does this one match? How do you know?
Partner talk: Does 13 + ____ = 16 match? How do you know?
I did a slow reveal of these number sentences to make sure students paid attention to each one individually. To do this, I just taped upside down index cards on my chart paper-it added mystery!
Directions: Students get a story problem with 4 equations. They have to determine which number sentence matches the story and prove it. The catch here is to remind students that they can't just look at the numbers!!
As a scaffold, there is a space for students to write the number that needs to go first, next and last. This will help students select an appropriate answer.
Cluck Cluck Problems are attached!
I'll have students share with a partner from the same group. To set students up for a deeper conversation (beyond the classic "I chose this because I thought in my brain"), I'll give a sentence frame and model using it. This helps kids practice CCSS MP3, Construct viable arguments, and develops their academic vocabulary. Academic vocabulary is a key part of the CCSS shift.
I know this equation matches because ____________. I'm sure this other equation does not match because ___________.
We will watch another form of CCSS aligned informational media, video! This video helps bring the text from the beginning of the lesson alive and shows one chick hatching in an incubator.