What is the composite number between 20 and 40?

1 Answer
George C.
Nov 14, 2016

All of the following are composite:

#20, 21, 22, 24, 25, 26, 27, 28, 30, 32, 33, 34, 35, 36, 38, 39, 40#

Explanation:

A composite number is any number which has factors apart from #1# and itself.

So most numbers between #20# and #40# are composite:

#20 = 2xx2xx5#

#21 = 3xx7#

#22 = 2xx11#

#24 = 2xx2xx2xx3#

#25 = 5xx5#

#26 = 2xx13#

#27 = 3xx3xx3#

#28 = 2xx2xx7#

#30 = 2xx3xx5#

#32 = 2xx2xx2xx2xx2#

#33 = 3xx11#

#34 = 2xx17#

#35 = 5xx7#

#36 = 2xx2xx3xx3#

#38 = 2xx19#

#39 = 3xx13#

#40 = 2xx2xx2xx5#

The only prime numbers (having no factors apart from #1# and themselves) between #20# and #40# are: #23, 29, 31, 37#.

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