expand

Everyday

1. To expand is to become bigger, or to make something bigger. tree →
2. To expand something like a business or town is to make it grow and cover more. tree →
3. To expand on an idea is to say or write more about it. tree →
4. In maths, to expand is to write something out in a longer form. tree →

In the lessons

In science, most materials expand when heated and contract (get smaller) when cooled — this is why bridges have gaps and why railway tracks have joints; water is unusual, expanding when it freezes, which can burst pipes. A balloon expands when you blow air into it. In maths, «expanded form» writes a number as the sum of its place values: 352 = 300 + 50 + 2. In writing, the teacher may ask you to expand your answer. Phrases: «expand on», «expanded form», «expand and contract».

Examples

• Metals expand when they get hot. tree →
• Water expands when it freezes, so a full bottle in the freezer can crack. tree →
• The balloon expanded as I blew into it. tree →
• Write 4,206 in expanded form: 4,000 + 200 + 6. tree →
• Please expand on your idea with an example. tree →
• The town expanded into the fields. tree →
• Your lungs expand when you breathe in. tree →
• The bakery expanded and opened a second shop. tree →
• "Travelling expands the mind very much," said the beetle. tree →

Note

Regular verb: expanded. Noun: expansion. Opposite: contract, shrink. In maths, expanded form adds up to the same number; it is only written differently. Do not confuse with «expend» (to use up).