Math Code

Primary (Age 6 – 9)

Curriculum Goal

Primary: Number Sense

  • Read, represent compose and decompose whole numbers up to and including 200, using a variety of tools and strategies, and describe various ways they are used in everyday life.
  • Determine what needs to be added to or subtracted from addition and subtraction expressions to make them equivalent.
  • Identify and use equivalent relationships for while numbers up to 100, in various contexts.


  • Students work in pairs.
  • Students should have prior experience with addition and subtraction.


In-person version

  • Writing tool
  • Paper
  • Pre-made math cards with different numbers and equations (Appendix A)

Online version


  • The goal of the game is to create pairs of equivalent numbers.
  • Students decide who is going to be the leader of the game by pulling a card from the deck. The player who pulls the highest number is the leader.
  • Players place the cards on the table face up.
  • The leader will select a card in their mind and provide their partner with a clue about that card in the form of an equation (e.g., 15-1).
  • The partner needs to look for two answer cards on the table: one with a whole number answer (I.e., 14) and one with an equation (I.e., 7+7). They must both be equivalent to the equation given by the leader.
  • Encourage students to discuss their strategies when choosing their cards. For example, students would express that 7+7=14, similarly to 15-1=14.
  • When the partner has identified the two equivalent cards, the leader will continue giving clues until all cards on the table are matched.
  • Students should be encouraged to use a piece of paper and a pencil if they are struggling to do the math in their mind.

Look Fors

  • Can students readily identify different equations to achieve the desired sum?
  • What strategies do children implement to determine the appropriate equations?
  • Can children add or subtract two single- or double-digit numbers?


  • Have two pairs of students create their own sets of cards and switch them to complete the game.
  • Create a more challenging set of cards that have a sum total greater than 100.
  • Integrate a card set with fractions.
  • Introduce multiplication and division number cards.

Created by Courtney Wickware. Adapted by The Robertson Program.

Related Lessons

Students find the sum of numbers and ensure they are equivalent to a sum or product that is a multiple of 10.

A possible follow-up activity, students flip two cards and determine numbers that add/subtract to a certain sum/difference.

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