Математика. Числительные. Аристова В.М. - 40 стр.

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БФУ им. Канта | Калининград

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40
Nought, O may often be omitted but the point (.) is never omitted because it
shows that the number is a decimal fraction. In the USA "O" is preffered to be read
as "zero".
The point (.) may be written in the upper, middle or down part of the decimal
fraction: 2.5; 2·5; 2˙5.
Ratio. Отношение.
a : b is read: the ratio of a to b; 10 : 5 is read: the ratio of ten to five;
4 : 2 = 2: the ratio of four to two is two.
20
5
=
16
24
: the ratio of twenty to five equals the ratio of sixteen to four; twenty is
to five as sixteen is to four.
Proportion. Пропорция.
In proportion we have two equal ratios. The equality is expressed by the sign ::
which may be substituted by the international sign of equality =.
a : b :: c : d or a : b = c : d — is read: a is to b as c is to d;
2 : 3 :: 4 : 6 or 2 : 3 = 4 : 6 — is read: two is to three as four is to six.
The extreme terms of proportion are called "extremes", the mean terms are
called "means". The proportion can vary directly (изменяться прямо пропорцио-
нально) and it can vary inversely (изменяться обратно пропорционально):
x ∝ y : x varies directly as y; x is directly proportional to y;
x = k/y: x varies inversely as y; x is inversely proportional to y.
Equations and Identities.
Уравнения и тождества.
There are different kinds of equations. In general the equation is an equality with
one or several unknown variable(s). The reading of equations is the same as in
Russian:
30 + 15 + x
2
+ x
3
= 90 — is read: thirty plus fifteen plus x squared plus x cubed is
equal to ninety. 
    Nought, O may often be omitted but the point (.) is never omitted because it
shows that the number is a decimal fraction. In the USA "O" is preffered to be read
as "zero".
    The point (.) may be written in the upper, middle or down part of the decimal
fraction: 2.5; 2·5; 2�5.
                                    Ratio. Отношение.
    a : b is read: the ratio of a to b; 10 : 5 is read: the ratio of ten to five;
    4 : 2 = 2: the ratio of four to two is two.
    20 16
      = : the ratio of twenty to five equals the ratio of sixteen to four; twenty is
    5 24
to five as sixteen is to four.
                                 Proportion. Пропорция.
    In proportion we have two equal ratios. The equality is expressed by the sign ::
which may be substituted by the international sign of equality =.
    a : b :: c : d or a : b = c : d — is read: a is to b as c is to d;
    2 : 3 :: 4 : 6 or 2 : 3 = 4 : 6 — is read: two is to three as four is to six.
    The extreme terms of proportion are called "extremes", the mean terms are
called "means". The proportion can vary directly (изменяться прямо пропорцио-
нально) and it can vary inversely (изменяться обратно пропорционально):
    x ∝ y : x varies directly as y; x is directly proportional to y;
    x = k/y: x varies inversely as y; x is inversely proportional to y.


                   Equations and Identities. Уравнения и тождества.
    There are different kinds of equations. In general the equation is an equality with
one or several unknown variable(s). The reading of equations is the same as in
Russian:
    30 + 15 + x2 + x3 = 90 — is read: thirty plus fifteen plus x squared plus x cubed is
equal to ninety.


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