Mentally Subtracting TwoDigit Numbers
How to mentally subtract two twodigit numbers.
 Subtract 35 from 84.
 First subtract the two tens' place digits (8  3 = 5)
 Notice that the bottom ones' digit is larger than the top ones' digit. Decrease
the answer for the tens' place by one (5  1 = 4) and increase the top ones' place value by 10
(4 + 10 = 14).
 Next subtract the two ones' place values (14  5 = 9)
 Combine the tens' and ones' place differences to make 49.

 Subtract 62 from 94.
 First subtract the two tens' place digits (9  6 = 3)
 Next subtract the two ones' place digits (4  2 = 2)
 Combine the tens' and ones' place differences to give the answer of 32
