Addition-And-Subtraction Wjec-Eduqas Higher

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Exam code:C300

Addition & subtraction

How do I add large numbers without a calculator?

There are a variety of written methods that can be used to add large numbers
- The order in which numbers are added is not important
The column method is the most commonly used hand written method
- The numbers are written one number above the other,
  - Line up the digits using place value columns
- Add each pair of corresponding digits from the top and bottom rows (work right to left)
- If the result is a single digit
  - write the result in the relevant place value column below the line
- If the result is a 2 digit number
  - the ones are written in the relevant place value column below the line
  - the tens are carried to the top of the next column
- If the addition of the final pair of digits results in a 2 digit number
  - write both digits below the line
For example, the addition 9789 + 563 = 10 352

How do I subtract large numbers?

A variety of written methods exist, but you only need to know one
- The order in which two numbers are subtracted is important so ensure the calculation is the right way round
The column method is the most commonly used hand written method
- The numbers are written one number above the other
  - Line up the digits using place value columns
  - The number being subtracted should be below the original amount
- Subtract each digit in the bottom value from the corresponding digit in the top value (work right to left)
- If the digit being subtracted is bigger than the one it is subtracted from
  - “borrow ten” from the next column to the left
For example, 392 – 28 = 364

What words are used for addition and subtraction?

Addition may be phrased using the words: plus, total or sum
Subtraction may be phrased using the words: difference or take away

Examiner Tips and Tricks

A good way to check your answer without a calculator is to estimate it
- e.g. if you work out 32 870 ÷ 865 to be 295, check by doing 30 000 ÷ 1 000 in your head which is 30, so your answer is probably wrong (the actual answer is 38)

Worked Example

(a) Find the sum of 3985 and 1273.

Notice that the word sum is used but this means add
Quickly estimate the answer

4000 + 1000 = 5000

Write the numbers in two rows and columns aligned

Start with the ones (units) column, writing the answer below the line but in the same column

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Maths Gcse Wjec-Eduqas Higher