Odds and Evens
An understanding of what is means for a number to be odd or even is essential for developing more complex mental arithmetic strategies and is also useful for checking the viability of a solution.
These are some of the basic concepts students should have developed by Year 4:
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In Year 4, we will apply this basic understanding to determine rules for addition, subtraction and multiplication of odd and even numbers. Students will work with manipulative materials, visual aids and numbers to discover generalisations such as an even number added to an even number results in an even number.
If a child has not yet developed an understanding of odd and even numbers, these activities may help:
- Here is a kid-friendly definition of odd and even numbers: Even numbers can be paired up exactly. Odd numbers can't.
- Tell kids that odd numbers are lonely, and even numbers have a friend. Show the written number 1, and have the child get one block or counter. Does 1 have a friend? No-so one is odd. Repeat with number 2 and notice that 2 has a friend: even. When you get to number 3 and above, make one pair of 2 friends, and put the third one by itself. 3 is lonely, so it's odd.
- Relate the terms odd and even to other uses of the words: "The groups are even". "There is an odd one out".
- Give a number from 1-10. Show kids how to count on their fingers, then "partner their fingers up". If any finger is all by itself, the number is odd.
- Give a random number of objects (e.g. buttons, beads, peas, eggs, forks, pegs, socks). They count them and say if it is odd or even then prove it by matching the objects with pairs.
- More simple practical ideas can be found on this website.