Lesson Guide
Explanation
Big numbers are built from blocks: ones, tens, hundreds and thousands. The magic rule is 'ten of everything': 10 ones make a ten, 10 tens make a hundred, and 10 hundreds make a thousand. So a number like 3472 just means 3 thousands, 4 hundreds, 7 tens and 2 ones — all stacked together.
Your Turn
How many tens make a hundred? How many hundreds make a thousand? Check: 10 and 10. It is always ten!
Watch Out
Don't mix up 'a ten' and the number 10 written with digits. A ten is a bundle of ten ones — one yellow block.
Explanation
To read a big number, go from left to right. 3472: say the thousands first — 'three thousand'. Then the hundreds — 'four hundred'. Then the rest like a normal two-digit number — 'seventy-two'. All together: three thousand, four hundred and seventy-two.
Your Turn
Read these out loud: 2315 and 6048. Check: 'two thousand, three hundred and fifteen' and 'six thousand and forty-eight'.
Watch Out
In 6048 there are no hundreds — so you don't say any hundreds. The 0 is quiet, but it still holds the spot.
Explanation
To write a number from words, give every place a digit — thousands, hundreds, tens, ones. 'Five thousand, two hundred and six': 5 thousands, 2 hundreds… no tens were said, so the tens spot gets a 0… and 6 ones. That makes 5206. If you skip the zero you get 526 — a completely different number!
Your Turn
Write these with digits: 'four thousand and thirty' and 'nine thousand, one hundred and one'. Check: 4030 and 9101.
Watch Out
The zero is the sneaky one. Every place needs a digit — if a place is not mentioned in the words, it gets a 0.
Explanation
A number line helps you see how big a number really is. To place 3500: first find the two thousands it sits between — 3000 and 4000. Then look at the hundreds: 500 is exactly half of 1000, so 3500 sits right in the middle between 3000 and 4000.
Your Turn
Where would 7900 go? Check: between 7000 and 8000, very close to 8000. And 2100? Between 2000 and 3000, close to 2000.
Watch Out
Don't just look at the first digit — 3900 and 3100 both start with 3, but they live at opposite ends of the same gap.
Explanation
You can count forwards or backwards in jumps of 1, 10, 100 or 1000. Only the matching digit changes… until it hits 9 and rolls over, like a car odometer. Watch 2997, 2998, 2999 — then everything rolls over to 3000. Counting by 1000 is the easiest: only the thousands digit changes: 6240, 7240, 8240.
Your Turn
What is 10 more than 4395? What is 100 less than 8020? What is 1 more than 6999? Check: 4405, 7920, 7000.
Watch Out
The tricky ones are the roll-overs — 1 more than 6999 is 7000, not 6 1000! When a column is full of 9s, they all tip over together.
Explanation
Zero looks like nothing, but it has a big job: it holds a place open. In 4052 the zero keeps the 4 up in the thousands place. If you drop the zero you get 452 — and the 4 has slid down to the hundreds. The number became about ten times smaller! So when you write numbers, every empty place must get its zero.
Your Turn
Write 'seven thousand and five' with digits. Check: 7005 — two zeros holding the hundreds and tens places. Now try the quiz tab and the exercises!
Watch Out
This is the most common mistake in the whole topic. Before you finish any answer, count your digits: numbers in the thousands need exactly 4 digits.
Step 1: Introduction
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