This one is set up to show that the sum of -4 and +2 is -2.

- -4 the addend, is on the bottom line,
- 2 the addend, is on the top line,
- - 2, the sum, is on the middle line.

### Components of a Nomograph

Each nomograph requires:

- A set of identical parallel number lines having scales lined-up one above the other.

- A middle or third number line placed parallel and midway between the first two.
- Each number on the middle number line is twice as large its corresponding
value on the outer number lines.

- A additional string or rigid line is needed to connect addends on the outer
lines and read the sum on the middle line.
- This rigid line must be able to reach from the left-most addend on the top line
- to the
- right-most addend on the bottom line.

### To Use a Nomograph to Add

- Stretch the rigid line from an added on the top line to the
other addend on the bottom line.
- Read the sum at the intersection of the rigid line and
the middle number line.

### To Use a Nomograph to Subtract

- Stretch the rigid line from the subtrahend on the top line through the minuend on the middle line
then continue the line to the bottom line.
- Read the remainder at the intersection of the rigid line and
the bottom number line.

### It Takes All Kinds

Use different scales to make different nomographs.

### A Nomograph Bulliten Board

Fill the bulliten board with directions, the 3 parallel number lines at a height convenient for students use. A string or stick must be available to strentch from -5 on the top to -5 on the bottom with the
string attached at the positive end of the number lines.