Numbers, units and arithmetic
Numbers, units and arithmetic

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Numbers, units and arithmetic

3.1 Arithmetic with whole numbers

When you are adding or subtracting whole numbers, an important thing to keep in mind is the place value of the figures. It is often a good idea to set out the numbers in columns before doing the arithmetic.

Example 11

  • (a) There are 4985 people living in a village and 93 people living in a nearby hamlet. How many people live in the village and the hamlet in total?

  • (b) Of the total number of people in the village and hamlet, 1352 are under voting age. How many people are eligible to vote?

Answer

  • (a) There are 5078 people altogether.

  •   

  • An alternative method is to note that 93 is 7 less than 100. So add 100 to 4985 (5085) and subtract 7 (5078).

  • (b) 3726 people are eligible to vote.

  •   

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