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- 98
- êêêMIXED NUMBERS, ADVANCED LEVEL
-
- è In this section we will be looking at the four operations of addi-
- tion, subtraction, multiplication, and division of signed fractions
- and/or mixed numbers.ïA signed fraction is just a fraction with either
- a plus or a minus sign attached to it like all the fractions in the In-
- termediate Level.ïA mixed number is a combination of a whole number and
- a fraction.ïFor example, six and three fourths is a mixed number.ïIt
- can be expressed in numeric form as, 6 3/4.ïEvery mixed number can be
- expressed as an improper fraction by multiplying the whole number times
- the denominator of the fraction and adding the result to the numerator.
- This sum is then placed over the denominator to get the equivalent of
- the mixed number in improper fraction form.
-
- Example 1)ïChanging a positive mixed number to improper fraction form.
-
- êêêè3ê(6∙4 + 3)ê27
- #êêê 6 -è=è─────────è=è──
- êêêè4êè 4êë4
-
- Example 2)ïChanging a negative mixed number to improper fraction form.
-
- êêêè2ê-(3∙5 + 2)ê-17
- #êêë - 3 ─è=è──────────è=è───
- êêêè5êë5êë 5
- It is very important that the minus sign is placed outside of the paren-
- çs in the first step.ïThus, every mixed number can be expressed as
- an improper fraction.ïThis is basically how we will work with mixed
- numbers.ïWe will change them to improper fractions, then add, sub-
- tract, multiply, or divide like we did in the Intermediate Level.ïThis
- process will be described in one rule after we look at a complete list
- 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 8)ïTo add, subtract, multiply, or divide a combination of mixed
- numbers and/or signed fractions, you should change all mixed numbers
- to improper fraction form then perform the operations as we did in
- the Intermediate Level.
-
- Example 3)
-
- ë1ë2ê-25è8ê-75è64ê-75 + (-64)ê-139
- # - 3 ─ - 2 ─è=è─── - ─è=è─── - ──è=è───────────è=è────
- ë8ë3ê 8è 3ê 24è24êè 24êê24
-
- Example 4)
-
- ê 1ë2ë-25è8ê-75è64ë -75 + 64ê-11
- #è - 3 ─ + 2 ─ï=ï─── + ─è=è─── + ──ï=è────────è=è───
- ê 8ë3ë 8è 3ê 24è24êè24êè24
-
-
- Example 5)
-
- ê 1ë3ê4è13ê4 ∙ 13ê52êè 7
- #ë 1 ─ ∙ 2 -è=è- ∙ ──è=è──────è=è──èorè3 ──
- ê 3ë5ê3è 5ê3 ∙ 5ê 15êè15
-
- Example 6)
-
- ë1è 5ê -5è 5ê-5è12ê-5∙12ê-3
- # - 1 ─ ÷ ──è=è ── ÷ ──è=è── ∙ ──è=è─────è=è──è=è-3
- ë4è12êï4è12ê 4è 5ê 4∙5êï1
-
- è Leon the Fraction Wizard prefers to use the above method to perform
- addition and subtraction of mixed numbers, but many people would rather
- add or subtract mixed numbers in a column.ïThis is also a very good way
- to perform ç two operations.ïOne advantage is that you can add or
- subtract the whole numbers and the fractions separately.
-
- Example 7)
-
- êêê 3êêêê21
- #êêë 2 -ë=ë2 ──ë=ë2 ──
- êêê 5êë 35êë 35
-
- êêê 1êêêê 5
- #êêè+ï5 -ë=ë5 ──ë=ë5 ──
- êêê 7êë 35êë 35
- #êêè───────ê ───────ê ───────
-
- êêêêêêêï26
- #êêêêêêê7 ──
- êêêêêêêï35
-
-
-