How many syllables in laundry?

The 'laun' in laundry would be the stressed syllable, because it's the part of the Word you give the most emphasis too.

LAUNdry sounds different than if you pronounce it launDRY. It's easier to spot stressed syllables if you try saying the syllable louder than the rest. If it still makes sense, then it's the stressed syllable.

For example:

Apple

Apple

Saying it incorrectly sounds odd, so that's the unstressed syllable.