Rules for Using Significant Figures in Mathematical Operations

Round down whenever the digit following the last significant figure is a 0,1,2,3, or 4. For example, 30.24 becomes 30.2. Round up whenever the digit following the last significant figure is a 6,7,8,9 or a 5 with any nonzero digit at any place after it. For example, 22.49 becomes 22.5. For example, 54.7511 round to the tenths place becomes 54.8. ................
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