Read, write, order, and compare numbers up to 10,000,000 and determine the value of each digit
You already know how to read and write numbers into the hundred thousands. Big counts need bigger groups, like how many people came to a city fair. Starting from the right, every three digits get grouped together with a comma. These groups are called ones, thousands, and millions. Inside each group the places work the same way. From left to right they are hundreds, tens, then ones. So the thousands group holds hundred-thousands, ten-thousands and thousands.
To read 4,302,561, split it at the commas: 4 million, then 302 thousand, then 561. Say each group as its own number, then add the group name: four million, three hundred two thousand, five hundred sixty-one.
Going the other way, from words to digits, the job is to fill every group. After the millions group, each group needs exactly three digits. When a group is missing its hundreds or its tens, a zero holds the empty space. Three million, twenty thousand, five gives 3 in the millions group, 020 in the thousands group, and 005 in the ones group: 3,020,005. Leave those zeros out and the number turns into a different one.
To compare two big numbers, count the digits first. More digits means a bigger number, so an eight-digit number beats any seven-digit one. If both numbers have the same number of digits, start at the leftmost digit and walk right. Equal digits tell you nothing, so keep walking. The first place where the two digits differ decides it, and whatever comes after that place does not matter.
Group digits in threes from the right, read each group by name, and compare numbers starting from the leftmost digit.
The rewritten readings were written for this dataset.
You can already read six-digit numbers by their comma groups: 302,561 is three hundred two thousand, five hundred sixty-one. Add one more group on the left and you are into the millions. The aquarium's visitor counter reads 4,302,561.
Split it at the commas: 4, then 302, then 561. What is that first 4 worth?
Jobs that lean on this skill. Follow one to see everything it is built on.
34 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.