过账时,有时把金额数码搞颠倒了,造成试算不平衡,这样的差错是常见的。但这类差错有着一个共同的特征,就是误差都是九的倍数。因此,在试算平衡时,遇到账平不起来,只要它们的差额正好是9的倍数,就可以考虑是否有哪一笔账在过账时把金额的数码搞颠倒了。譬如把12写成21,差额是9;把380写成830,差额是450;……等等。我们可以用方程式把颠倒数的误差总是9的倍数,表示出来。假设有一个二位数,它的个位数字是x,十位数字是y(x与y都代表9以内的正整数和零)。则这个二位数的代数式可写成(10y+x),它的颠倒数的代数式就是(10x+y)。如 Posting, sometimes the amount of digital upside down, resulting in trial imbalance, such a mistake is common. However, this type of error has a common characteristic, that is, errors are multiples of nine. So when you try to balance the balance, you can not figure it out, and as long as the difference is exactly a multiple of nine, consider whether there is an account that has reversed the figure at the time of posting. For example, 12 written as 21, the difference is 9; the 380 written 830, the difference is 450; ... and so on. We can use the equation to show that the error in the inversion is always a multiple of nine. Suppose you have a two-digit number that has the unit digit x and the ten digit y (both x and y represent a positive integer equal to zero and zero). Then the two-digit algebra can be written as (10y + x), and its algebraic inversion is (10x + y). Such as