Main objective of the lesson: Understanding the equal sign to make a sentence true, using
addition equations.
What pre-requisite skills do the students need to be successful at this objective: Assume
nothing for prerequisite skills ~ differentiate quickly.
Students who will need extra support during this lesson: This will be a hands-on lesson that
is supported by differentiation strategy.
Students who will understand the concept quickly: Students will move on to hundreds mixed
with tens and ones.
Materials: scales, base-ten blocks, notebooks, equal sign, Elmo projector
Key Vocabulary: symbol, equal sign, equation
*Start by showing the students the = sign in my notebook projected on the Elmo. Give the
students two minutes to write down in their notebooks everything they know about this symbol.
*Discuss ideas on what this symbol means (very important for understanding their background
knowledge)
*I started the lesson with a balance scale, asking the students if they knew what it was, what it
was used for, where they have seen it.
*First I placed ones on one side, for example 5, on the other side of the scale I put two in. I asked
the students how we could balance it and how they knew it would be balanced. I did these using
a few more examples of ones blocks and for values under ten. (I found over ten then scale had a
hard time balancing due to the different make of base-ten blocks)
* Next, I had the students write the equations we had down in their notebooks with me. This is
where the discussion came in on why one number was on one side and how we could add two
numbers on the other but they were still equal.
* When I wrote the equation I started with 5 = 2 + ⃞. One student immediately said I wrote the
equation the wrong way so that lead us into another discussion.
* Then, partner students up based on level of understanding- have them complete a 10 problems
using the scale to balance and find the solution. I had numbers greater than 10, I would keep
them under 10 for this concrete part. The larger numbers were too hard to keep concrete with the
base ten blocks.
*If partners were higher-level, I had them complete equations in the hundreds.
*This is an investigation lesson that can go a lot of direction depending on the students
understanding and background lessons. I made sure to move the equal sign and have addition
sentences on both sides, or leave different numbers out.
Game:
(Adapted from Becky Berg, Billings Public Schools Instructional Math Coach)
What you need:
2 players
deck of cards, face cards removed
cut a 3×5 card in thirds. On two of the thirds write a + sign. On the last third write an = sign.
Shuffle the cards and deal six cards to each player. Stack the rest of the cards facedown in a pile.
Each player chooses four cards from his/her hand. The object is to balance the equation by
arranging the cards into two addition problems with equal sums. A player earns one point for
balancing the equation.
Example: a player could place a 7 and a 1 on one side of the equation and a 3 and a 5 on the
other (7+1 = 3+5)
A player can also place two cards of the same value on the equation to balance it (4+0 = 0+4).
At the end of a round, the cards played are placed at the bottom of the deck. The dealer shuffles
the cards and gives six more to each player. Play continues in the same way.
The game ends when one player reaches ten points.
Variation: Children can play a similar game using subtraction or addition and subtraction.
Change your “operation cards” so that children can create various balancing equations.
Reflection:
● they knew what the equal sign was
● understood the symbol
● like keeping the box as the missing symbol
● keep the numbers under 20; play around more with lower numbers
● build with two different numbers on each side of the equal side (14 + 6 = 7 + 13)
● students were having a hard time keeping track of what they had added into the balance
Follow-up:
● continue to work with smaller numbers
● math mat where students “match” the place value blocks on each side