Operations with decimals

Decimals add, subtract, multiply and divide like whole numbers, as long as the decimal points line up.

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Add or subtract: line up the points, work column by column.
Multiply by a whole number: ignore the point, multiply, then put the point back.
× 10, 100, 1000: move the point right. ÷: move it left.

2.5 + 1.75

2.50 + 1.75

4.25

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Add a zero to make the lengths match: 2.5 = 2.50.

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