Level 1: Odd, even and sharing

Number theory · level 1 of 8 · rough age 5-6 (a guide for parents; anyone can start anywhere)

Number theory is the part of math about whole numbers: 1, 2, 3, 4, and so on. It starts with a question you can answer with socks and sweets: does everything have a partner, or is one left over? In this level you learn odd and even, fair sharing, skip counting, the numbers that make rectangles, and what a leftover is. Every lesson has pictures, things to try with real objects, and answers to check.

Lesson	You will be able to
Pairs: everything has a partner	Line things up two by two and say if a number is even (all partners) or odd (one left over)
Odd and even on the number line	See that odd and even take turns, and tell any number's kind from its last digit
Fair sharing between two friends	Share counters fairly between two people, and know before you start whether one will be left
Skip counting by 2s, 5s and 10s	Skip count on a number line, with hands and with nickels, and say which numbers you land on
Rectangle numbers	Build rectangles from counters, and find which numbers up to 12 make a rectangle and which only make a line
Leftovers	Share among 3, 4 or 5 friends, find the leftover, and explain why it is always smaller than the number of friends

Next: Level 2: Factors and multiples · Back to the topic: Number theory