**MACHINE SHOP CALCULATION - OD1640 - LESSON 2/TASK 3**

column adds up to 60 or more, proceed similarly, remembering that seconds

change to minutes and minutes to degrees.

EXAMPLE

Take away 60" from 81" and

add 1' to 133'. Then take

away 120' from 134' and add

2,, to 58,,. After becoming

accustomed to this procedure,

the values can be carried to

their respective columns mentally.

b.

To subtract angles, arrange the degrees, minutes, and seconds in

separate columns, with the larger angle on top.

Then subtract the

individual columns. If the upper number in a column is too small to allow

subtraction, one unit must be taken away from the following column and 60

units added to the insufficient number.

This makes the subtraction

possible.

EXAMPLE

Subtract 14,, 51' 30" from 86,, 45' 10".

Here the subtraction cannot be

performed in either the seconds

or the minutes columns.

Hence take away 1' from 45'

leaving 44', and add 60" to 10",

getting 70". Also, take 1,,

from 86,,, leaving 85,,, and add

60' to 44', getting 104'.

c.

To multiply an angle by a number, it is necessary to multiply each

column by the given number. Then, if the answers in the "seconds" or the

"minutes" columns are greater then 60, they must be reduced, as in the

addition of angles.

**57**