Help with Maths

4T5

4T5

4T5

Man of Honour
Joined
30 Aug 2004
Posts
27,737
Location
Middle of England
:o For starters !!!

I need help with long multiplication as after not doing any for around 25 years I've forgot how to do it :(
The sum i need to understand & have explained is 25.00 x 1.6 but I can't for the life of me remember how to convert it & then do the reverse.
So could some kind person write it out here so i can get my head around it again.
Appreciate the help & Accept the embarrassment :)
 
This might not be the most helpful way of doing it but I'd split the 25 into 5x5 and split the .6 into fifths i.e. you have 3 fifths of a whole one so you get 3x5 giving 15 and that takes care of the .6 then add the original 25 to give a total of 40.

Now that probably doesn't make a lot of sense in a description but I've tried to make it as clear as I can.
 
vaultingSlinky said:
Break the 1.6 into 0.6 and 1. 25 times 1 = 25. 25 times 0.6 is the same as 2.5 times 6 which = 15.

Add the 2 together 25 + 15 = 40. (same as 1.6 x 25)
Click to expand...

This works in my head mate but i need the "Solution" is it called ?
You know the Move the point here do this there sort of answer.



Good to see you as well mate :)
 
1.6 x 10 is 16.

16 x 2.5 = 40.

To simplify the 16 x 2.5 - it's 16 x 2, plus half of another 16.
 
vaultingSlinky said:
I guess you can move the point 'to the right' (essentially x10) on the 1.6 to get 25 x 16 which = 400. You then have to move the decimal point to the left (divide by 10...on 400.0) and that gives you the answer (40)

Good to see you too hehe, never see you on xbl tho!
Click to expand...


Cooking with Gas now mate :cool:

You'll see me more on Live nowadays, Am hooked up till 20th April Big Thanks to Hilly & feek :cool:
We have community PGR4 nights so get your 15 quid out & get down the super cheapo high street store. :D
 
A more general answer, because it only works quite so nicely because it is 2.5, is:

Remove all decimal points by pushing them to the right.
1.6 becomes 16 (remember we moved the point 1 place)
25.00 leave this as 25, (I know I just said remove the decimal point but 25.00 is clearly 25 so imagine the decimal point was never there)

16 x 25 = ?

Code: 
  16
x 25
----
  80   (5 * 16)
+320   (add a zero on the right because we are now in the 10s column, 2 * 16)
----
 400   (answer)

Now because we removed "one decimal place", add it back in
so 400 becomes 40.0. That is 40 :)
 
You must log in or register to reply here.
Back
Top Bottom