Reading 5-digit numbers

In your book, Maths Mela (Chapter 1, We the Travellers — I), we start with 1,000 and keep adding a thousand: 1,000, 2,000, 3,000 … 9,000. What do we get when we add one more thousand to 9,000? We get ten thousand, written 10,000.

So the place value chart needs a new column on the left, TTh, for ten thousands. Each place is 10 times the place on its right: 10 ones = 1 ten, 10 tens = 1 hundred, 10 hundreds = 1 thousand, and 10 thousands = 1 ten thousand = 10,000. The chart now has five places: TTh, Th, H, T, O.

We use a comma to help us read big numbers. The comma goes after the thousands, so 45,867 has 4 ten thousands and 5 thousands before the comma, and 8 hundreds, 6 tens and 7 ones after it. We read it as forty-five thousand eight hundred sixty-seven: first the number before the comma with the word 'thousand', then the rest. In the same way, 10,024 is ten thousand twenty-four, 13,520 is thirteen thousand five hundred twenty, and 20,000 is twenty thousand.

When a place has a 0, we say nothing for it. 36,001 is thirty-six thousand one: 0 hundreds and 0 tens are not read out. But when we WRITE a number from its name, every empty place still needs its 0. Ninety thousand nine is 90,009.

We can also write a number in expanded form, as the sum of what each digit is worth. 783 = 700 + 80 + 3. 10,304 = 10,000 + 300 + 4, because it has 1 ten thousand, 0 thousands, 3 hundreds, 0 tens and 4 ones. We leave out the places that have 0.