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- 65
- êêïMULTIPLYING FRACTIONS, INTERMEDIATE LEVEL
-
- è In this section we will be looking at multiplying positive and/or
- negative fractions.ïYou recall in the Elementary Level that when you
- multiplied two positive fractions, you always got a positive fraction
- as an answer.ïIn this section we are really considering multiplying
- any fraction, positive or negative, times any other fraction, positive
- or negative.ïThere will be two rules to cover the different cases.
- The first rule is used when multiplying two fractions that are both
- positive or both negative.ïThe second rule will be for multiplying two
- fractions with different signs.ïThe following list shows the set of all
- fractions.
- êêêêïFractions
-
- #êë ... -╩ï-╔è╚è╔è╩è╦è╠è═è╬ ...
- êêè 1è1è1è1è1è1è1è1è1
-
- #êë ... -╩ï-╔è╚è╔è╩è╦è╠è═è╬ ...
- êêè 2è2è2è2è2è2è2è2è2
-
- #êë ... -╦ï-╔è╚è╔è╩è╦è╠è═è╬ ...
- êêè 3è3è3è3è3è3è3è3è3
- êêêê.
- êêêê.
- êêêê.
-
- Rule 4)ïTo multiply two fractions that are both positive,ïyou should
- multiply them like we did in the Elementary Level.ïTo multiply two
- fractions that are both negative, just multiply the two numerators and
- the two denominators remembering that the product or quotient of two
- negative numbers is positive.ïThen, cancel like factors and simplify.
-
- Examples
-
- ï1) Both fractions positive.
-
- ê 5è 9ê 5∙9êè 5∙3∙3êë1êè1
- #ê── ∙ ──è=è─────è=è ─────────è =è ───è =è ─
- ê12è15ê12∙15ê 2∙2∙3∙3∙5êï2∙2êï4
-
- 2) Both fractions negative.
-
- è -2è-3ë -2 ∙-3ê 6êè 2∙3êë1êè1
- #è ── ∙ ──è=è─────è=è───è=è─────────è=è─────è=è──
- ë9è 8ê9 ∙ 8ê9∙8ê3∙3∙2∙2∙2ê3∙2∙2ê12
-
- Rule 5)ïTo multiply two fractions that have different signs, just
- multiply the two numerators and the two denominators remembering that
- the product or quotient of a positive number and a negative number is
- negative.ïThen, cancel like factors and simplify.
-
- 3) One fraction positive and the second fraction negative.
-
- êê2è-3ê2∙(-3)ê2∙(-3)ê-3
- #êê─ ∙ ──è=è──────è=è──────è=è──
- êê7è10ê 7∙10êï7∙2∙5ê35
-
- 4) The first fraction negative and the second fraction positive.
-
- êë -1è12ê-1∙12ê-1∙2∙2∙3ê-3
- #êë ── ∙ ──è=è─────è=è────────è=è──
- êê4è 5ê 4∙5êè2∙2∙5êï5
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