#real_number__real  any rational or irrational number
  supertype:  complex_number__complexnumber__complex_quantity__complexquantity__imaginary_number__imaginarynumber  a number of the form a+bi where a and b are real numbers and i is the square root of -1
  subtype:  scalar_product__inner_product__innerproduct__dot_product__dotproduct  a real number (a scalar) that is the product of two vectors
  subtype:  rational_number  an integer or a fraction
     subtype:  fraction  the quotient of two rational numbers
        subtype:  mantissa__fixed-point_part__fixedpointpart  the positive fractional part of the representation of a logarithm; in the expression log 643 = 2.808 the mantissa is .808
        subtype:  common_fraction__simple_fraction  the quotient of two integers
           subtype:  half__one-half__onehalf  one of two equal parts of a divisible whole; "half a loaf" or "half an hour" or "a century and one half"
              subtype:  fifty_percent__fiftypercent  a half expressed as a percentage
              subtype:  mediety__moiety  one of two (approximately) equal parts
           subtype:  one-third__onethird__third__tierce  one of three equal parts of a divisible whole; "it contains approximately a third of the minimum daily requirement"
           subtype:  two-thirds  two of three equal parts of a divisible whole
           subtype:  one-fourth__onefourth__fourth__quarter__fourth_part__twenty-five_percent__quartern  one of four equal parts; "a quarter of a pound"
           subtype:  three-fourths__threefourth  three of four equal parts; "three-fourths of a pound"
           subtype:  one-fifth__onefifth__fifth__fifth_part__fifthpart__twenty_percent  a fifth part
           subtype:  one-sixth__onesixth__sixth  a sixth part
           subtype:  one-seventh__oneseventh__seventh  a seventh part
           subtype:  one-eighth__oneeighth__eighth  an eighth part
           subtype:  one-ninth__oneninth__ninth  a ninth part
           subtype:  one-tenth__onetenth__tenth__tenthpart__ten_percent__tenpercent  a tenth part; one part in ten
           subtype:  one-hundredth__onehundredth__hundredth__onepercent  one part in a hundred
           subtype:  one-thousandth__onethousandth__thousandth  one part in a thousand
           subtype:  one-millionth__onemillionth__millionth  one part in a million
           subtype:  one-billionth__onebillionth__billionth  one part in a billion
           subtype:  one-trillionth__onetrillionth__trillionth  one part in a trillion
           subtype:  one-quadrillionth__onequadrillionth__quadrillionth  one part in a quadrillion
           subtype:  one-quintillionth__quintillionth  one part in a quintillion
        subtype:  improper_fraction  a fraction whose numerator is larger than the denominator
        subtype:  proper_fraction__properfraction  a fraction with a numerator smaller than the denominator
           subtype:  decimal_fraction__decimalfraction__decimal  a proper fraction whose denominator is a power of 10
              subtype:  circulating_decimal__circulatingdecimal__recurring_decimal__recurringdecimal__repeating_decimal__repeatingdecimal  a decimal with a sequence of digits that repeats itself indefinitely
        subtype:  complex_fraction__complexfraction__compoundfraction  a fraction with fractions in the numerator or denominator
        subtype:  continued_fraction__continuedfraction  a fraction whose numerator is an integer and whose denominator is an integer plus a fraction whose numerator is an integer and whose denominator is an integer plus a fraction and so on
  subtype:  irrational_number  a real number that cannot be expressed as a rational number
     subtype:  transcendental_number  an irrational number that is not algebraic
     subtype:  algebraic_number__algebraicnumber  root of an algebraic equation with rational coefficients
     subtype:  3.14159265358979323846...__pi  the ratio of the circumference to the diameter of a circle
     subtype:  e__2.718282...  the base of the natural system of logarithms

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