It's important to understand numbers when you listen; for example, when you listen to detailed information on a TV or radio program or during a lecture.
Numbers ending in -teen or -ty canbe difficult. You need to listen carefully for the stress patterns in these numbers. That way you can be sure you understand the numbers correctly.
• In numbers ending in -ty, the first syllable is stressed : FIF-ty.
• In numbers ending in -teen, the stress is on the last syllable : fif-TEEN.