Reading and writing numbers (age 9+)
Read, write, order, and compare whole numbers up to at least 1,000,000 using base-ten numerals, number names, expanded form, and place-value understanding
What a learner can do afterwards
- Write 403,072 in words and in expanded form
- Compare 548,301 and 543,801 using < and explain the reasoning
- Order four six-digit numbers from smallest to largest
The lesson
A number with six or seven digits looks long, but it is built the same way every time. Every three digits form a group: ones, then thousands, then millions. A comma marks where each new group starts.
To read 403,072, read each group like its own small number, then add the group name. The first group is 403, so say four hundred three. Then say thousand. The last group is 072, so say seventy-two. Altogether: four hundred three thousand, seventy-two.
Expanded form breaks a number into the value of each digit, added together. For 403,072, that is 400,000 + 3,000 + 70 + 2. For 1,340,000, that is 1,000,000 + 300,000 + 40,000.
You already know how to compare numbers by checking digits from the left. Do the same with big numbers: line up the digits, then find the first spot where they differ. Whichever number has the bigger digit there is the bigger number.
Read a number group by group, write it in words or expanded form, and compare big numbers by finding the first digit that differs.
Watch it
Where it sits
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.