How do you solve #3.15\div 0.45#?

1 Answer
Jim G.
Dec 5, 2016

#7#

Explanation:

The first step is to convert the 2 decimal numbers into whole numbers.
This is achieved by #color(blue)"multiplying both numbers by 100"#

#rArr3.15÷0.45=3.15/0.45larr" in fractional form"#

#=(3.15xx100)/(0.45xx100)=315/45larr" whole numbers"#

We can now #color(blue)"cancel"# these numbers by dividing both by the same #color(blue)"common factor"#

Since both numbers have a last digit of #color(red)(5)# this means that they are divisible by 5.

#rArr(315÷5)/(45÷5)=63/9=7larr" if you know 9 times table"#

This is usually written as: #cancel(63)^7/cancel(9)^1=7#

Otherwise repeat the process, using a factor of #color(red)(3)#

#rArr63/9=cancel(63)^(21)/cancel(9)^3=21/3=7larr" 3 times table"#

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