expansion

Everyday

1. Getting bigger in size, amount or space. tree →
2. (science) The way a material takes up more space when it gets warmer. tree →
3. The growth of a business, a town or an empire into new places. tree →
4. (maths) Writing a number or an expression out in a longer form, such as 345 = 300 + 40 + 5. tree →

In the lessons

In science it describes heat making solids, liquids and gases expand: railway tracks have gaps for expansion. In maths «expanded form» or «expansion» means writing a number as a sum of its place values, or multiplying out brackets. In history and business it means growing into new lands or markets. Phrases: rapid expansion, expansion of the town, thermal expansion.

Examples

• The expansion of the balloon showed that the air inside was getting warmer. tree →
• Bridges have small gaps to allow for expansion on hot days. tree →
• The expansion of the school means we will get a new library. tree →
• Write 4,562 in expanded form: 4,000 + 500 + 60 + 2. tree →
• The company's expansion brought new jobs to the town. tree →
• The Roman Empire's expansion covered many lands. tree →
• Water's expansion when it freezes can crack a pipe. tree →

Note

Verb: expand; adjective: expansive (wide, open, or friendly and chatty). The opposite is contraction. Spelling: -sion, not -tion. In maths, expansion does not change the value: 345 and 300 + 40 + 5 are equal.