 ## Curriculum Goal

#### Primary: Number Sense

• Read and represent whole numbers up to and including 50.
• Describe various ways whole numbers may be used/referenced in everyday life.
• Compose and decompose whole numbers, up to and including 50, using a variety of tools and strategies, in various contexts.

## Context

• Teacher works with at least two children.

## Materials

• Deck of cards with face cards removed (Ace = 1)

## Lesson

Easier Version:

• Lay cards face-down randomly in a 5 × 8 rectangle.
• Explain that the goal is to match cards of the same number. Colour/suit do not matter.
• For each round, students turn over one card and try to find a matching card.
• Introduce the advanced version, if appropriate.

• Explain that the goal is to find the numbers that add/subtract to a certain sum/difference (chosen from a number between 2-20).
• Give an example, such as 5. Ask students for different number pairs for that sum (e.g., if the chosen sum = 5, players should aim for Ace + 4 or 9 – 4; if the chosen difference = 3, players should aim for pairs such, as 6 – 3 and 1 + 2).
• When all pairs for the predetermined difference have been found, facilitate a discussion about how quantities can be composed and decomposed.
• Challenge the students play the game in pairs.
• Afterward, hold a discussion to extend student thinking. Here are some sample questions:
• How did you know these pairs were correct?
• What strategies did you use to add/subtract the two cards together?
• What techniques did you use to remember where the cards were?
• Why would there be more possible pairs for a larger difference (i.e., 10 versus 5)?

## Look Fors

• Do the children select the exact card that they were looking for?
• Are students counting the number of symbols on the card? If so, are they using one-to-one correspondence? Are the students recognizing the numbers on the card?
• Are the children using their fingers to count? Are the children counting up or counting on when they choose their pairs?
• Do the children use certain memory strategies to determine if the pairs create the predetermined sum?
• Do the children use mathematical language to talk about the cards?

## Related Lessons

Compose numbers up to and including the number 50 using different strategies.