Place value can be used to subtract 4.23 and 2.75 because in order to subtract, you must line up the whole numbers together, the tenths place together, and the hundredths place together.
Lining them up: Whole= W Tenths place= T Hundredths place= H
W T H
4 . 2 3
- 2 . 7 5
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1 . 4 8