standard_description: Add and subtract within 20, demonstrating fluency for addition and subtraction within 10. Use strategies such as counting on; making ten (e.g., 8 + 6 = 8 + 2 + 4 = 10 + 4 = 14); decomposing a number leading to a ten (e.g., 13 – 4 = 13 – 3 – 1 = 10 – 1 = 9); using the relationship between addition and subtraction (e.g., knowing that 8 + 4 = 12, one knows 12 – 8 = 4); and creating equivalent but easier or known sums (e.g., adding 6 + 7 by creating the known equivalent 6 + 6 + 1 = 12 + 1 = 13).
problem_activity: Stage 2: Factors and Multiples
Required Preparation
Materials to Gather
Centimeter cubes
Materials to Copy
Blackline Masters
Find the Number Stage 2 Directions and Gameboard

Narrative
Students find factors and multiples for a given number. To start, one player chooses an even number less than 50. The other player covers either a factor or multiple of that number. Students take turns covering either a multiple or factor of the previous number. When there are no factors or multiples left to cover, the player who covered the last number gets a point. Students take turns choosing the starting number. Students play 10 rounds, as time allows, and the player with the most points wins.
Additional Information
Each group of 2 needs 100 centimeter cubes.


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