Grade 1 & 2
- Estimate the number of objects in a set, and check by counting
- Demonstrate, using concrete materials, the concept of one-to-one correspondence between number and objects when counting
- Represent, compare, and order whole numbers to 50, using a variety of tools
Presented to entire class in a circle formation on the carpet. Once demonstration is complete, students work independently or in pairs with materials on the carpet or seated at their desks.
- Several containers filled with either buttons, beads, etc
- Download: Recording sheet
- 100s chart for reference
The children are introduced to the idea of estimation. The educator demonstrates the activity to the group. The children then select target numbers and attempt to scoop the number of small objects (e.g., buttons) with their hands without counting. They count the amount they collected and compare the total with their target number. They determine if they had too many or too few, and try again.
- Present the idea of estimation through a group discussion while sitting in a circle.
- Discuss real life example of using estimation (e.g., estimating how much money to bring to the grocery store, how much shampoo to put into your hand to wash your hair, etc.).
- Instruct the children to engage in “think, pair, share”, discussing times they think they used estimation.
- Facilitate a group discussion of the examples they came up with.
- Demonstrate estimation activity to children in the circle.
- Count out 10 items from the container and model thinking about how 10 feels and looks.
- Ask students to pick a number between 15-30. Once a number is selected, explain that this number is the “Target Number” and that their goal is to try, without counting, to scope up that number using their hands.
- Model scooping and thinking about whether you think it’s close to your target.
- Count out your first try (option to model counting by 2s).
- Compare how many you collected with your target number and ask students to decide if you gathered too many or too few.
- Repeat steps 6-10 and think out loud about how you can try to get closer to your target number.
- Demonstrate writing and recording your target number, first try and second try as well as whether there were too many or too few.
- Emphasize that getting close to the target number is the goal. the goal is not to get the exact number.
- Distribute containers of objects and recording sheets and have students do the activity, supporting students when necessary.
- Give students the option to work in pairs and take turns being the recorder and the estimator.
- Assign number ranges (e.g., 15-30) for students, depending on their grade level but do not exceed 40.
- Take into consideration the size of their hands and the objects they’re working with.
Look For and Questions to Extend Student’s Thinking
- What did you do to try and get closer to your target number?
- Just by looking, how many do you think there are?
- Did knowing what 10 looks/feels like help you?
- Do children have one-to-one correspondence between number and objects when counting?
- Do they move the object to make it easier to count?
- Do they count by 1s or do they attempt to count by 2s?
- Do they just know which is more or less or do they attempt addition and subtraction? Educator can assess the child’s number sense and if the child understands that “each number in sequence refers to a set of a particular size.”
- If they engage in addition or subtraction to find out how many more or less they had compared to their target number, what strategies do they use: counting on or down from their target number?
- Are they getting closer to their target number on their second try? Can they explain the strategies they used to get closer to their target number?