A

**number line** represents the value of a number as a distance from zero.

The ticks on the number line are 4 units apart.

The dot is one tick mark to the right of 291.

Add 4 to 291 to find the number represented by the dot on the number line.

The ticks on the number line are 3 units apart.

The dot is two tick marks to the right of 128.

Add 3 to 128 two times to find the number that Z represents.