Recognizing, reading and writing numbers
Recognizing Numbers
- Whole numbers, also known as integers, include zero and all positive and negative numbers without any fractional or decimal part.
- Roman numerals are an example of non-decimal numbers, such as I, V, X, L, C, D, and M.
- Number systems, such as binary and hexadecimal, are used in computer science. Binary numbers use only 0 and 1, while hexadecimal employs digits from 0 to 9 and letters from A to F.
Reading Numbers
- Understand the place value system when reading numbers. For instance, in the number 1234, 1 is in the thousands place, 2 is in the hundreds place, 3 is in the tens place, and 4 is in the ones place.
- Be able to read large numbers by breaking them into chunks of threes, starting from the right. The first group is hundreds, next is thousands, and then millions.
- Become familiar with number prefixes such as uni-, bi-/di-, tri-, quad, penta-, hexa-, hepta-, octo-, nona-, deca-.
- Know special names for numbers like zero, one, two up until twenty, and then thirty, forty, fifty, going up in decades until one hundred.
Writing Numbers
- Always write numbers as simply as possible. Avoid writing out long complex numbers without good reason.
- Be consistent when writing out numbers – ensure to stick with either words or figures throughout a piece of writing.
- Understand the proper usage of hyphens when writing numbers between twenty-one and ninety-nine.
- If a sentence begins with a number, write it out in words, e.g., Two hundred people attended the event.
- Use commas to separate every three digits from the right when writing large numbers, i.e., 1,000; 20,000; 300,000; 4,000,000.
- Place a zero in front of a decimal if the number is less than one, such as 0.25 instead of .25.
- Develop the ability to express numbers in scientific notation using powers of ten, this helps to write extremely large or small numbers in a concise way.