Reaction Math would probably improve your mental arithmetic skills, then.
]]>12345-6789
= (+6000)-444
= 5556Using my method this would only take a second or two...
youre method is the way i usually would do these sort of things in my head, but when its something thats not so easy i would have to write it down on paper, im not too good with mental arithmetic
]]>Hope you like the method.
]]>1098-772
(772+300)+26
1098-772 = 326
---
Example 2;
5897-2653
(+3000)+200+44
= 3244
Example 3:
2097152-524288
(+1500000)+(73000)-136
= 1572864
The 136 was subtracted from my answer because I went over.
]]>= (+6000)-444
= 5556
Using my method this would only take a second or two...
]]>Another example;
12253-591
=591+10000+1500+162
Occasionally I might do it a different way. But I have been able to tackle every subtraction problem so far with this method.
For 12253-591, rather than using my method I would just do:
(12253-600)+9
= 11662.
]]>mathsyperson wrote:Seriously? You'd start at 123 and count until you got to 456? That would take you ages and be fairly pointless, considering the triviality of the sum. I'm probably misunderstanding you. Any other way though, and you'd have to do it in more than one step.
A bit like number lines. For 456-123, I would do: 123 + 300 + 33.
Hard to explain.
Now I think I get it to give another example:
521-214
you'd do:
214+300+7= 521
so the difference is 307
]]>Seriously? You'd start at 123 and count until you got to 456? That would take you ages and be fairly pointless, considering the triviality of the sum. I'm probably misunderstanding you. Any other way though, and you'd have to do it in more than one step.
A bit like number lines. For 456-123, I would do: 123 + 300 + 33.
Hard to explain.
]]>