In principle the amount can not be far beyond the merepractice, but try the steps slower and slightly changing the focus on the steps of the sum with a little practice can go veryfast.
First a very simple exercise that quickly becomes complicatedbut to expand your ability to add up.
You start with 0 and you add 1 after you add the result 2, thenyou add the new result on 3 so far as you can. For the images;
0 +1 +2 +3 +4 +5 +6 +7 +8 +9 +10 .... etc.
What can not you see? ! No problem
0 +1 = 1 +2 = 3 +3 = 6 +4 = 10 +5 = 15 +6 = 21 +7 = 28 +8 = 36 ....
Well, just do it to make it habitable once a day much as you can every day. Gradually'll earn further and faster.
Now for the tricks;
Quick Sum a column of numbers (1).
Strategy: adding from left to right one by one or all the digits inthe tens, then units. This applies to less than one hundredumber. In the following example the tens digit is added before the units digit, this is an example;
account:
11 11
75 86 (70 +11 = 81 +5 = 86)
34 120 (80 +30 = 110 +6 = 116 +4 = 120)
68 188 (120 +60 = 180 +8 = 188)
49 237 (or 188 +50 = 238-1 = 237)
26 263 (response)
------
263
And this column can do sums quickly.
