3.1.7. Translate into Russian:
•To convert an improper fraction into a mixed number, break it up into the sum of an integer and a proper fraction
•To reduce a fraction to its lowest terms, divide the numerator and the denominator by their highest common factor (or: measure, or: divisor)
•To find the sum (the difference) of two unlike fractions, change them to like fractions (fractions having their least common denominator) and combine the numerators
•To find quotient of two fractions, multiply the dividend by the inverted divisor
•To find the product of two fractions, multiply the numerators together and the denominators together
•To reduce a fraction to higher terms, multiply the numerator and the denominator by the same number.
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Unit 4.Decimal fractions |
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Look through the table and try to memorize it. |
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writing |
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reading |
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.2 |
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Point two |
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0.2 |
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O point two, or; two tenths |
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0.02 |
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O point o two, or; two hundredths |
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12.707 |
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Twelve point seven o seven |
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0 |
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O, or: zero, or: nought; or: cipher; or: nil |
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(null) |
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4.1 TEXT (Read the text and do the tasks that follow.)
FRACTIONS
There are three methods of dealing with fractions:
1.by expressing each fraction as the sum of fraction as the sum of fractions with unit numerators, e.g.
56 = 12 + 13
2.by diving the unit into sub-units which are given special names, e.g. the foot is divided into twelve parts and each twelfth part called an inch;
3.by using fractions whose denominators are powers of the same number, e.g.
34 = 107 + 1005
The Egyptians used the first method and developed a high degree of skill in it. The second method was used by the Romans, who divided their pound, their foot and one of their coins into twelfths; these fractions were called unciae, from which we get
12
the words inch and ounce. The third method dates back to the Babylonians, who used fractions with denominators which were powers of 60; the Greeks also this method in scientific work.
It was not until Simon Stevin (1548-1620) published his essay on decimal fractions in 1585 that the third method, with denominators which all powers of 10, became generally adopted. Stevin was an important government official in the Netherlands in the time of the struggle against Spain. Many authors had used decimal fractions in particular problems, and decimal point first appeared in print as early as in 1492, but Stevin was the originator of general rules for the use of decimal fractions.
4.1.1Choose the best sentences ending which is true to the text: 1.The Egyptians used
a.the second method of dealing with fractions.
b.the first method of dealing with fractions and developed a high degree of skill in it.
c.fractions called unciae.
d.fractions with denominators which were powers of sixty.
2.The third method dates back to
a.The Roman period.
b.1585 when Simon Stevin published his essay on decimal fractions.
c.Ancient times
d.The Babylonians, who used fractions with denominators which were powers of sixty
4.1.2 Choose the best reply to the sentences given.
1.What was Stevin’s contribution in mathematics?
a.He used decimal fractions in particular problems.
b.He was the originator of general rules for the use of decimal fractions.
c.He used decimal fractions in particular problems.
d.He developed the first method of dealing with fractions.
2.What times does the third method date back to?
a.It dates back to ancient Rome.
b.It dates back to the fourteenth century
c.It dates back to Babylonians.
d.It dates back to the twentieth century.
4.1.3 Rearrange the words to make sentences. 1.with three are methods of dealing There fractions.
2.method The used Egyptians the first.
3.in print decimal as early in as 1492 point appeared The first.
4.2 Assignments
4.2.1.Memorize the following words and word-groups:
decimal fraction |
[`desIm(q)l`frxkS(q)n] |
Десятичная дробь |
13