Zero represents "nothing" or an empty set. It is the number we use when there are no objects to count. Zero is just as important as other numbers in helping us describe quantities.
Start with concrete experiences: empty containers, empty hands, "no more blocks left." Use zero in real contexts like "zero cookies in the jar." Play games where children count backward to zero.
Children may not understand that zero is a real number. They might think counting always starts at one. Some may confuse zero with the letter O.
Zero is the number of things in an empty collection. It sounds simple, but zero is one of the most powerful ideas in mathematics — and one of the most recently invented. For most of human history, people used numbers only to count things that were there, and "nothing" didn't seem to need a number. Recognizing zero as a number, not just an absence, is a genuine conceptual achievement.
Start with what you can see. If there are three apples on a plate and you eat all three, how many apples are left? Zero — the plate is empty. Zero isn't "nothing to say"; it's something precise to say: there are zero apples. The bowl, the jar, the hand can all be described with a number even when there's nothing in them. Zero is the name for that amount.
Zero has a fixed location. It lives on the number line before 1, not after 10. When you count backward — 5, 4, 3, 2, 1, 0 — you land on zero after you pass 1. This is why we count down from zero in games and launches: zero is the arrival point, the moment before we start. Understanding where zero sits in the counting sequence helps you see that numbers don't have to start at 1 — you can always ask "what comes before 1?" and the answer is zero.
Later, zero will do even more work: it holds a place in numbers like 10 and 20 (the zero in "10" tells you there are no ones), it anchors the number line as the dividing point between positive and negative numbers, and it plays a special role in addition and multiplication. For now, the most important thing is simply that zero belongs — it is a real number, a member of the counting family, with its own place and its own meaning: none at all.