One of the ASVAB problems that would-be soldiers have to face is how to perform detailed mathematical calculations without calculators. A math trick on how to quickly divide numbers that end in zero without having to write down detailed calculations.
By now you might think that not all numbers appearing in ASVAB end in zero and require a concatenation. Note, however, that asvab math exercise often provides approximate answers. So if you get an answer that is close enough to the real one, it can help rule out the wrong decision because it is so far away.
So, if you need to do a calculation that doesn't always end in zero, just round your number to zero and then do the math trick. If you divide a number by a factor of 10, i.e. For example, dividing 10 by 10 is 1. This may be intuitive to you since the number dividing by itself is one.
But think differently. The number 10 ends with zero. This means that you subtract a factor of 10. On paper, this means taking the imaginary decimal point at the end of a number and moving it one space to the left.
Let's apply this to more complex numbers. If you have the number 30 and you divide by 10, 30 divided by 10 equals 3. You can imagine moving an invisible decimal point from zero to between 3 and 0 and getting the number 3.
Now something more complicated, 231 divided by 10. Again, take the imaginary decimal point after 1, shift it over to space and the result is 23.1