Odd & Even Numbers

A number is EVEN when everything can be put into pairs with nobody left over. Six socks make three tidy pairs — 6 is even. Eight is even too. Think of lining up for partners: if everyone gets a partner, the number is even.

A number is ODD when pairing up always leaves exactly one left over. Five dots make two pairs… and one lonely dot. Seven makes three pairs and one left over. Every whole number is either odd or even — there's no in-between.

You don't need to pair up four thousand dots to test 4736! Here's the trick: only look at the LAST digit. If it ends in 0, 2, 4, 6 or 8, the number is even. If it ends in 1, 3, 5, 7 or 9, it's odd. Why does this work? Because tens, hundreds and thousands always split into pairs perfectly — only the ones can leave a leftover.

Students often wonder about numbers ending in 0. They are even! Forty splits into twenty pairs with nothing left over. Skip counting by 2 starting at 0 — 0, 2, 4, 6, 8, 10, 12… — lands on every even number. Starting at 1 — 1, 3, 5, 7, 9, 11… — lands on every odd number. The two counts never touch.

Here's something magical: you can predict whether an answer will be odd or even before adding! Even plus even is always even — pairs plus pairs stay pairs. Odd plus odd is EVEN — the two leftovers find each other and pair up! Odd plus even stays odd — one leftover stays lonely. Try it: 3 + 5 = 8. Two odds made an even, just like the rule promised.

Odd and even pop up everywhere — house numbers on opposite sides of the street, sharing between friends, teams and partners. Detectives use the rules: 'I am even, bigger than 46 and smaller than 50' — the numbers between are 47, 48, 49, and only 48 is even. Case closed! Now it's your turn in the quiz and exercises.