Mental division: 150/120 is 1.25. Obviously I know that the answer is 1.something but why .25?

[math student 2934839]

Hi,

I have a simple question, but I need help with how to do basic division problems mentally without a calculator.

So for example: 150/120 is 1.25. Obviously I know that the answer is 1.something but why .25? Pretty embarrassing question but I guess my knowledge there is lacking.

I really appreciate any help. Thanks

 

[Dr.Peterson]

Hi,

I have a simple question, but I need help with how to do basic division problems mentally without a calculator.

So for example: 150/120 is 1.25. Obviously I know that the answer is 1.something but why .25? Pretty embarrassing question but I guess my knowledge there is lacking.

I really appreciate any help. Thanks

If I came across this problem, I would change it to fractions, which makes it easier.

 

[AvgStudent]

Hi,

I have a simple question, but I need help with how to do basic division problems mentally without a calculator.

So for example: 150/120 is 1.25. Obviously I know that the answer is 1.something but why .25? Pretty embarrassing question but I guess my knowledge there is lacking.

I really appreciate any help. Thanks

I would do something like this (mentally).

[math]\dfrac{150}{120} = \dfrac{120+30}{120} = \dfrac{120}{120} + \dfrac{30}{120}= 1 + \dfrac{1}{4}=1.25[/math]

 

[pka]

For example: 150/120 is 1.25. Obviously I know that the answer is 1.something but why .25? Pretty embarrassing question but I guess my knowledge there is lacking.
I really appreciate any help.

If I were presented with the term [imath]\dfrac{150}{120}[/imath] I would see it as [imath]\dfrac{15}{12}=\dfrac{5}{4}[/imath].

 

[Steven G]

30/120 = 1/4 = .25