CAPTIVATING SUM

That it is easier to add round numbers like 40 or 50 than numbers ending in 7, 8, or 9. If you round these awkward numbers up by adding 3, 2 or 1 the calculation is not much longer, and is easier.
Instead of
49+52 = 101
think of it as
50 (that is 49+1) + 52 = 102-1 = 101
Other example
If you are adding
215
426
513
112
328
----

First add the figure in the hundreds column and hold the total, 1500, in your head. Now add the total of the tens column, 70, to it. To this total 1570 add the sum of the units column, 24, to arrive at the final total of 1594.

EXAMPLE.

Even when you use pencil and paper carrying error can occur. Here is a method of working which makes them much less likely.

----9845674
----7465387
----8236472
----4578348
----3847568
----3569841
----------------
----4200960
---3334233
----------------
---37543290

Another method of avoiding carrying also involves adding each column separately. the column totals are set out in a staggered line, the units figure of the second column below the tens figure of the first, the units figure of the third column below the tens figure of the second ans so on. the column totals are then added to given the final answer. Here is an example

----962853 ----------- 19
----524861 ---------- 22
----212346 --------- 24
----401258 -------- 13
----864321 ------- 28
-------------------------------------
------------------2965639