1. Topic-
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| Communicating about "difference" in Math |
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2. Content-
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Standards: 2.NBT.B.7 Add and Subtract within 1000, 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
Vocabulary: difference, compare, greater, less, equal |
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3. Goals: Aims/Outcomes-
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1.SW use a strategy to solve a word problem involving subtraction.
2.SW model this strategy using a pictorial representation.
3.SW explain the strategy used to solve the problem. |
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4. Objectives-
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1.SM use strategies such as making/breaking apart 10/100, doubles,
taking apart numbers, counting on/back to subtract, making an easier
problem.
2.SM use and explain strategies for addition and subtraction based
on concrete models, place value, properties of operations and/or the
relationship between adding and subtracting. |
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5. Materials and Aids-
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| Math journals, 11 highlighters, Base 10 blocks, counters, 100 number
chart, number line, plain paper for "posters," writing and coloring
tools. |
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6. Procedures/Methods-
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A. Introduction-
1.TW explain that we are going to find the "difference" between
2 groups. TW ask the S to think about what mathematical operation
they will use to find the "difference" between 2 numbers.
2.TW ask how many S are in class today. SW count and answer.
3.TW pass out highlighters to 11 of 24 S.
4. TW ask, "How many S did not get a marker?" |
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B. Development-
| 1. TW review prior knowledge of strategies S can use to find the
"difference" between those who have and those who don't have highlighters.
(Listed under objectives). |
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C. Practice-
1. SW independently use their own math journal to write out a solution
to the problem using a subtraction strategy to find the "difference."
2. TW ask leading questions to help S figure out a way to find the
difference between the 2 groups and what that has to do with how many
S do not have a highlighter.
2. When most S have completed their own thinking, TW form groups of
3 to communicate each of their strategies to one another within the
group.
3.Through communication, groups will decide upon one strategy that
leads to a solution to the problem, "How many S do not have a highlighter?" |
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D. Independent Practice-
1. Groups will create a "poster" showing a pictorial representation,
number representation and words to describe their thinking to solve
the problem.
2. TW pull a name stick to decide which group can present 1st. The
person whose name is pulled will present the group strategy.
3. Groups will communicate their agreed upon strategy to find the
difference to the class.
4. WG will discuss the strategy presented and decide if the strategy
led to a correct answer in an efficient manner. |
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E. Accommodations (Differentiated Instruction)-
1.Use any of manipulatives provided.
2.Show place value chart
3.Use subtraction algorithm |
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F. Checking for understanding-
| 1.Each group will be assessed for understanding based on their choice
of strategies, path to the correct answer and whether they can see
the connection between how many did not have a highlighter and the
difference between 2 groups. |
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G. Closure-
1. Did we find a solution to the problem "How many students did
not have a highlighter?"
2.How is the solution to that question related to the difference between
2 groups?
3. Did talking about the problem with your group help you to understand
a connection between the "difference" and how many in the groups? |
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1.Posters
2.Math Journals |
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8. Teacher Reflection-
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| Extension: TW pose another problem using the same format-a large
group of kids (at soccer camp) with not enough of something (soccer
balls). TW ask the same question, "How many campers don't have a ball?"
SW connect that the two groups are being compared and that the difference
between them is the number that don't have a soccer ball. |
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