Partition & rename numbers (expanded notation)
Theory
Partitioning and renaming numbers is a Year 5 place value skill: writing a number in expanded notation as the sum of the value of each digit, splitting it into other parts that add to the same total, and renaming it as so many thousands, hundreds or tens. This Year 5 maths page explains each step with six- and seven-digit numbers, the role of zero, and how to find missing parts.
Expanded notation writes a number as the sum of the value of each digit: \(52\,407 = 50\,000 + 2000 + 400 + 7\).
In charts and working, HTh means hundred thousands, TTh ten thousands, Th thousands, and H, T, O hundreds, tens and ones.
To partition a number is to split it into parts that add back to the number. Standard partitioning uses place value parts, but you can also use other parts: \(437\,215 = 400\,000 + 37\,215\) or \(437\,215 = 430\,000 + 7215\).
To rename a number is to say it using a different unit. \(437\,215\) is \(437\) thousands, \(2\) hundreds, \(1\) ten and \(5\) ones. It is also \(4372\) hundreds and \(15\) ones.
A zero digit is worth nothing, so it gets no term in expanded notation: \(708\,040 = 700\,000 + 8000 + 40\).
Expanded notation and renaming both use place value:
How to write expanded notation
- Name the place of each digit, starting from the left.
- Write its value: the digit followed by the right number of zeros.
- Add the values, leaving out any zero digits.
How to write a numeral from expanded notation
- Find the largest place used, so you know how many digits the number has.
- Place each value in its column.
- Fill empty places with zeros.
How to complete a partition
- Subtract the part you know from the whole number.
- Check by adding the two parts back together.
| \(6 \text{ HTh}\) | \(=\) | \(600\,000\) |
| \(5 \text{ TTh}\) | \(=\) | \(50\,000\) |
| \(1 \text{ Th}\) | \(=\) | \(1000\) |
| \(384\) | \(=\) | \(300 + 80 + 4\) |
Add the four lines: \(651\,384\) is the sum of the value of each digit.
| \(308\,090\) | \(=\) | \(300\,000 + 8000 + 90\) |
The ten thousands, hundreds and ones digits are zero, so they have no term.
| \(\text{HTh, TTh, Th}\) | \(:\) | \(2,\ 0,\ 9\) |
| \(\text{H, T, O}\) | \(:\) | \(0,\ 7,\ 1\) |
The number is \(209\,071\). Zeros hold the empty ten thousands and hundreds places.
| \(519\,600 - 400\,000\) | \(=\) | \(119\,600\) |
The missing part is \(119\,600\). Check: \(400\,000 + 119\,600 = 519\,600\).
(i) \(357\,400 = 300\,000 + \underline{\qquad}\)
(ii) \(357\,400 = 350\,000 + \underline{\qquad}\)
(iii) \(357\,400 = 357\,000 + \underline{\qquad}\)
| \(357\,400 - 300\,000\) | \(=\) | \(57\,400\) |
| \(357\,400 - 350\,000\) | \(=\) | \(7400\) |
| \(357\,400 - 357\,000\) | \(=\) | \(400\) |
(i) \(57\,400\).
(ii) \(7400\).
(iii) \(400\).
(ii) How many hundreds are in \(61\,900\)?
(iii) How many thousands make \(9\) million?
| \(8\,350\,000\) | \(=\) | \(8350 \text{ thousands}\) |
| \(61\,900\) | \(=\) | \(619 \text{ hundreds}\) |
| \(9 \text{ million}\) | \(=\) | \(9000 \text{ thousands}\) |
(i) \(8350\).
(ii) \(619\).
(iii) \(9000\).
| \(283\,560\) | \(=\) | \(283\,000 + 500 + 60\) |
\(283\) thousands, \(5\) hundreds and \(6\) tens.
| \(\text{the } 3\) | \(=\) | \(3 \text{ thousands}\) |
| \(\text{Noah's sum}\) | \(=\) | \(630\,200\) |
The \(3\) is worth \(3000\), not \(30\,000\), because a zero holds the ten thousands place. The correct expanded notation is \(600\,000 + 3000 + 200\).
Common pitfalls
Frequently asked questions
What is expanded notation?
Expanded notation writes a number as the sum of the values of its digits. For example, \(84\,036 = 80\,000 + 4000 + 30 + 6\).
What happens to zeros in expanded notation?
A zero digit is worth nothing, so it has no term. \(308\,090\) is \(300\,000 + 8000 + 90\).
What does partition mean?
To partition a number is to split it into parts that add back to the whole. \(357\,400\) can be split as \(300\,000 + 57\,400\) or \(350\,000 + 7400\).
How do you find a missing part of a partition?
Subtract the part you know from the whole number. For \(519\,600 = 400\,000 + \text{?}\), the missing part is \(119\,600\).
How many thousands are in a number?
Cover the last three digits and read what is left. \(8\,350\,000\) has \(8350\) thousands.
How many thousands make a million?
One million is \(1000\) thousands, so \(9\) million is \(9000\) thousands.