Arithmetic and pre-algebra Fractions Number sets Number Sets Number Sets 1 Number Sets 2 Number Sets 3 Number Sets Number Sets Back Number Sets ⇐ Use this menu to view and help create subtitles for this video in many different languages. You'll probably want to hide YouTube's captions if using these subtitles. Consider the numbers 1/3 , 7 , -15 To which of these sets of numbers these numbers belong to. Lets review each of these Natural numbers are counting numbers not equal 0. it is 1,2,3,... so on and so forth The whole numbers are natural numbers plus 0 Whole numbers are 0,1,2,3,4 The integers is the whole numbers plus opposite of it It is whole numbers plus negative of natural numbers like -4,-3,-2,-1 0, 1, 2, 3,4, ... so on and so forth rational numbers are numbers that can be expressed as a ratio of two integers.Rational number can be expressed as m/n where m and n are integers and n cannot be 0 as anything divided by 0 is not defined. But m could be 0 as 0 can be expressed as 0/1 or 0/2 or 0/3 or 0/-537 these are all representations of 0 Irrational numbers are numbers that cannot be expressed as ratios of integers examples of irrational numbers are numbers that keeps repeating on and on and on π, √2 are examples of irrational numbers and then real numbers are really all of these combined if you are combining the rational numbers and irrational numbers you are talking about real numbers.every real number is either rational or irrational. lets classify what we have 1/3 is not a natural number as it is not a counting number. It is not a whole number it is not an integer.is it a rational number sure it is as 1 and 3 are integers. so 1/3 is a rational number.if something is rational it cannot be irrational and it is also a real number lets try 7 number 7 is a natural number, whole number any natural is a whole number any natural and whole number si an integer so 7 is also a integer. any number that is natural, whole and integer is a rational number. we can write 7 as 7/1 we can write any integer as that number / 1 if it is rational it cannot be irrational. it is also going to be real we have -15. it is not a natural number natural number are positive integers only it is not a whole number it is an integer, it is the opposite of +15 it is rational as it can be written as -15/1 and because it is rational it cannot be irrational Questions Tips & Feedback Be specific, and indicate a time in the video: At 5:31, how is the moon large enough to block the sun? Isn't the sun way larger? Have something that's not a question about this content? Post a tip or feedback General discussion about the site Report a technical problem with the site Request a video or feature This discussion area is not meant for answering homework questions. Formatting tips Cancel or ( total) Share a tip When naming a variable, it is okay to use most letters, but some are reserved, like 'e', which represents the value 2.7831... Suggest a fix At 2:33, Sal says "double bonds" but should say "single bonds." Have something that's not a tip or feedback about this content? Ask a question General discussion about the site Report a technical problem with the site Request a video or feature This discussion area is not meant for answering homework questions. Formatting tips Cancel or Discuss the site For general discussions about Khan Academy, visit our Reddit discussion page. Flag inappropriate posts Here are posts to avoid making. If you do encounter them, flag them for attention from our Guardians. abuse disrespectful or offensive an advertisement not helpful low quality not about the video topic soliciting votes or seeking badges a homework question a duplicate answer repeatedly making the same post wrong category a tip or feedback in Questions a question in Tips & Feedback an answer that should be its own question about the site a question about Khan Academy (Visit our FAQ) a post about badges a technical problem with the site (Report a problem) a request for videos or features
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