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Mathematics 21 Online
OpenStudy (bluemiku):

Is the number 15 prime or composite? A. prime B. composite

OpenStudy (anonymous):

can you factor 15 as a product of two other numbers ?

OpenStudy (bluemiku):

umm i dont think so

OpenStudy (skullpatrol):

Divide it by 3

OpenStudy (bluemiku):

hold on..

OpenStudy (skullpatrol):

$$\Huge 15 \div 3= ?$$

OpenStudy (bluemiku):

ok i got it its composite!

OpenStudy (anonymous):

multiplication table (memorizing it) comes in handy here if the number is an answer to any product i.e. if it appears anywhere in the multiplication table then it is composite

OpenStudy (skullpatrol):

Good job :)

OpenStudy (bluemiku):

thank you guys so much! :)

OpenStudy (skullpatrol):

Thanks for asking!

OpenStudy (skullpatrol):

You can find the positive factors of a given positive integer by dividing it by positive integers in order.

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