How do i solve 562.34-64.89 and show my work

Best to write this problem as shown below:

562.34
 -64.89
    First, estimate the correct answer.  It would be 562-65 = 497.

Must borrow from the tenths column, because 9 is greater than 4.  We end up with 5 under the 4 and 9.  We must borrow again to obtain the next digit:

12-8=4, so the result is now .45

11-4=7, so the result is now 7.45

55-6=9, so the result is now 97.45.

Finally, 4-0=4, so the final result is 497.45.  Compare this to the estimate (497).

Here we've had to borrow 4 times.

3. 2, 5, 10, 50, 500, 25000, 12500000