Answer: (1) d, f   (2) c, d, f   (3) e, f    (4) a, b, c, d, f   (5) e, f
Step-by-step explanation:
a) Natural Numbers: Â Â Â Â Â Â 1, 2, 3, ...
b) Whole Numbers: Â Â Â Â Â 0, 1, 2, 3, ... Â Â (add zero to the Natural numbers)
c) Integers: Â ..., -3, -2, -1, 0, 1, 2, 3, ... Â (add negatives to the Whole numbers)
d) Rationals: Add terminating and repeating decimals to Integers.
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e) Irrationals: Non-repeating decimals that are non-terminating. Â This is its own category so cannot be a Rational number or above.
f) Real Numbers: ALL of the above (a - e) are Real numbers.
1) -5.2 Â has a terminating decimal so it is a RATIONAL number.
2) -4 Â is below zero so is an INTEGER which means it is also a RATIONAL #
3) -4.3212... is a non-terminating decimal so it is an IRRATIONAL number
4) [tex]\sqrt4[/tex] = 2 is a NATURAL number which means it is also a WHOLE number, INTEGER, and RATIONAL number.
5) [tex]\sqrt7[/tex] Â is a non-terminating decimal so it is an IRRATIONAL number