To round the following numbers to one significant figure, we will work through each one step by step, explaining the process:
a) 276 040
For this number, we want to keep the first non-zero digit and replace the others with zeros:
- The first significant digit is 2.
- We count all digits after the first significant digit (that are part of the number itself and not a decimal fraction). There are five digits following the 2.
- The rounded number will therefore be 2 followed by five zeros: 300,000.
b) £238.02
Here we have a monetary value, and we want to keep only the most significant digit:
- The first significant digit is 2.
- Since 3 is the next digit, rounding will affect the digit we keep. Rounding up, the 2 becomes a 3 because the digit immediately after it (the 3) is 5 or greater.
- The pounds should be rounded as a whole number, and the pence can be disregarded for our purpose.
- The rounded value is: £300.
c) 17 521 km
This distance value, in kilometers, is rounded as follows:
- The first significant digit is 1.
- All other digits are replaced with zeros while keeping the magnitude of the number.
- The rounded value is: 20,000 km.
d) 15°C
When rounding temperature values:
- The first significant digit is 1.
- As the next digit is a 5, which is 5 or greater, we have to round up.
- The rounded value of the temperature is: 20°C.
Note that for "Cloudy," that is not a numeric value and therefore cannot be rounded according to significant figures. It is a descriptive term related to the weather.
