### Theory:

Positive and negative integers

Numbers less than \(0\), are called negative integers. Negative numbers can be a whole number or fraction, for example, \(-1\), \(-2\), \(-0.7\), $-\frac{2}{3}$.

Numbers greater than \(0\), are called positive integers. Positive numbers can be a whole number or fraction, for example, \(3\), \(2\), \(8\), $1\frac{3}{17}$.

Important!

Note that the number \(0\) is neither positive nor negative.

Positive numbers, negative numbers (integers and fractions) and zero are called rational numbers.

Here, the numbers can be in fractional form.

$\begin{array}{l}\frac{p}{q}\phantom{\rule{0.147em}{0ex}},\mathit{where}\phantom{\rule{0.147em}{0ex}}p,q\to \mathit{Integers}\phantom{\rule{0.147em}{0ex}}\mathit{and}\phantom{\rule{0.147em}{0ex}}q\ne 0\\ \phantom{\rule{1.029em}{0ex}}\end{array}$

Every day, we use negative numbers when it comes to air temperatures, like minus six degrees or \(6\) degrees below zero.

That means that the thermometer is \(6\) degrees down from zero.

Looking at the mercury thermometer, we can observe that \(0\)$\mathrm{\xb0}$\(C\) (zero degrees Celsius) is in the middle.

Upwards are the positive degrees (\(1\), \(2\), \(3\), ...), usually denoted by red (hot).

Downwards are the negative degrees (\(-1\), \(-2\), \(-3\)...), usually denoted by blue(cold).

Looking at the mercury thermometer, we can observe that \(0\)$\mathrm{\xb0}$\(C\) (zero degrees Celsius) is in the middle.

Upwards are the positive degrees (\(1\), \(2\), \(3\), ...), usually denoted by red (hot).

Downwards are the negative degrees (\(-1\), \(-2\), \(-3\)...), usually denoted by blue(cold).

Similarly, the Number line works similar to the example as mentioned above.