Indicate the following using $ ''+'' $ or $ ''-'' $ sign:
 $ {{7}^{\circ }}C $ below the freezing point

Hint: As we are asked to represent $ {{7}^{\circ }}C $ with a sign which is below the freezing point. So we will find out the standards which say about the sign we used in writing the temperature below and above freezing point. And write the $ {{7}^{\circ }}C $ according to it.

Complete step by step answer:
Moving ahead with the question, when temperature is calculated in degrees Celsius then it is standard that $ {{0}^{\circ }}C $ is counted as a freezing point. And the temperature above it that is $ {{1}^{\circ }}C,{{2}^{\circ }}C $ will count as $ +{{1}^{\circ }}C,+{{2}^{\circ }}C... $ so on. But when we go below freezing point i.e. below $ {{0}^{\circ }}C $ then we will count as $ -{{1}^{\circ }}C,-{{2}^{\circ }}C... $ so on. So if we are given below freezing point then we will use the $ ''-'' $ sign with temperature and if we go above freezing point then we will use the $ ''+'' $ sign with temperature.
So we want to calculate for $ {{7}^{\circ }}C $ which is below the freezing point, so as above mentioned we will use $ ''-'' $ with temperature, so we will write $ {{7}^{\circ }}C $ below freezing point as $ -{{7}^{\circ }}C $ .
Hence the answer is $ -{{7}^{\circ }}C $ .

Note: Freezing point is counted as ${{0}^{\circ }}C$ when we count temperature in Celsius, the value of freezing point changes when we use any other unit of temperature. It is standardly recognised that temperature below freezing will be used with negative signs.