2. Decimal Basics This unit on decimals shows students how to read, write, compare, order, add and subtract decimals. Other topics include estimating decimal sums and differences, and solving word problems. Definition: A decimal is any number in our base-ten number system. Specifically, we will be using numbers that have one or more digits to the right of the decimal point in this unit of lessons. The decimal point is used to separate the ones place from the tenths place in decimals. (It is also used to separate dollars from cents in money.) As we move to the right of the decimal point, each number place is divided by 10.
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4. So why do we use decimals? Decimals are used in situations which require more precision than whole numbers can provide. A good example of this is money: Three and one-fourth dollars is an amount between 3 dollars and 4 dollars. We use decimals to write this amount as $3.25.A decimal may have both a whole-number part and a fractional part. The whole-number part of a decimal are those digits to the left of the decimal point. The fractional part of a decimal is represented by the digits to the right of the decimal point. The decimal point is used to separate these parts.