Large numbers are grouped in threes, separated by commas. Each group is a period.
Period is a group of three digits in a large number, like the thousands period.
Step 1: Let's Learn
Read it, or press Listen and follow the words.
Read one period at a time
342,715 reads as "three hundred forty-two thousand, seven hundred fifteen".
Expanded form
342,715 is 300,000 + 40,000 + 2,000 + 700 + 10 + 5.
Zeros still hold places
In 40,006 the zeros keep the 4 and the 6 in their proper places.
Step 2: Try It Yourself
Tap and try it out.
Hundreds
7
Tens
1
Ones
5
seven hundred fifteen
700 + 10 + 5 = 715
7 hundreds, 1 ten and 5 ones is 715.
Step 3: In Real Life
A city’s population
A city has 254,000 people. Two hundred fifty-four thousand. Newspapers, road signs and census forms all write and read numbers this size.
Step 4: Watch an Example
One step at a time.
Watch Leo Read 342,715
Leo is asked to read 342,715 out loud.
- Step 1
He finds the comma, which splits the number into two periods.
Step 5: Your Turn
Practice makes it stick.
Writing It Down
Problem 1 of 2
What is 40,000 + 3,000 + 200 + 6 in digits?
The Missing Tens
Problem 2 of 2
In 50,904, what is the 9 worth?
Read and Write
1 of 3
20,000 + 5,000 + 400 + 30 + 1 in digits?
2 of 3
In 87,502, what is the 7 worth?
3 of 3
How many digits are in each period?
Find It on the Chart
Build it, then check.
Find 120 on the chart.
Step 6: Quick Check
Show what you know.
Question 1 of 2
60,000 + 700 + 8 in digits?
Question 2 of 2
What does a comma do in a large number?
What You Learned
- Large numbers are grouped in periods of three.
- Read one period at a time, then say its name.
- Expanded form shows what each digit is worth.
For the grown-up
This lesson is where the child reads and writes multi-digit numbers in numerals, words, and expanded form. Each place is ten times the one to its right, and that single rule generates the whole system all the way to a million and, later, all the way down past the decimal point.
Watch for large numbers read digit by digit. "Four hundred and seven thousand" is a structure; "four zero seven" is a phone number.
Have them say the number aloud before working with it. Most errors with big numbers are reading errors that the arithmetic then faithfully preserves.
Numbers are read in groups of three — The commas in 348,275 split the number into periods: 348 thousands and 275 ones. Read each group as an ordinary three-digit number and say the period name after it: "three hundred forty-eight thousand, two hundred seventy-five". The commas are a reading aid, nothing more.
Writing from words — To write "sixty thousand, four hundred five", build it period by period: 60 in the thousands period, 405 in the ones. That gives 60,405. The zeros are essential — they hold the empty places open, and leaving one out shifts every digit to its left.
Expanded form for large numbers — 348,275 is 300,000 + 40,000 + 8,000 + 200 + 70 + 5. Writing it out this way makes each digit's value explicit, and it is exactly the decomposition that column addition relies on. Expanded form is not busywork; it is the algorithm written honestly.
A note on the word "and" — In careful mathematical reading, "and" marks the decimal point, so 405 is "four hundred five", not "four hundred and five". Everyday speech uses "and" freely and no one will misunderstand you. Knowing the convention matters most when decimals arrive.
Read it in groups of three — 3 4 5 6 7 8. Split it from the right into threes: 345,678. Read the left group, then say its name: three hundred and forty-five thousand. Then read the last group: six hundred and seventy-eight. The comma is not decoration. It tells you where to breathe.