GCSE Maths Addition And Subtraction
Introduction
A fundamental skill in the area of maths is the ability to be able to and subtract correctly. For the GCSE Maths exams there is a non calculator paper, so having strong GCSE Maths addition and subtraction skills is a must.
The methods used here will follow that of the column method where numbers are placed correctly according to place value. It is important to place numbers directly underneath each other.
GCSE Maths Addition and Subtraction Examples
Work out 2347 + 581
Your layout need to be as follows:
\begin{array}{r} 2347 \\ +\quad 581 \\ \hline 2928 \end{array}Example - Subtraction
The column method for subtraction is used just as we have seen for addition.
Work out 3407 – 1625
Your layout needs to be as follows:
\begin{array}{r} 3487 \\ -1625 \\ \hline 1782 \end{array}You do need to be careful with subtraction especially if the number being subtracted is bigger than the number that it is being subtracted from.
The method used in the example seen for subtraction is known as borrowing or exchange.
Quite often within GCSE Maths exams questions you will see worded problems that involve addition and/or subtraction. With these questions it is important to extract the appropriate information and then determine if you need to add or indeed subtract or even in some cases, both.
Worded maths question example 1:
Solution
34-15+17=36Worded maths question example 2:
Solution
33-19+15=29Worded maths question example 3:
Solution
For part (a) of the question you are asked to find a total cost. This means that you need to perform an addition.
\begin{array}{r} 0.75 \\ +1.60 \\ \hline 2.35 \end{array}For part (b) of the question you need to find the cost of each item remembering that 2 sandwiches are bought and to add all these amounts together.
\begin{array}{r} 0.70 \\ 0.85 \\ +2.70 \\ \hline 4.25 \end{array}When it comes to addition and subtraction maths questions you always need to be looking at the words with the question as quite often you find the clues that you need to help you answer the question. The fact that in part ( c ) of the question it is asking about “change” then this means that you need to perform a subtraction.
But first you need to find the total cost of all items bought:
\begin{array}{r} 0.75 \\ 0.85 \\ +1.35 \\ \hline 2.95 \end{array}The change given can then be found as follows:
\begin{array}{r} 5.00 \\ -\quad 2.95 \\ \hline 2.05 \end{array}Worded maths question example 4:
Solution
To be able to answer this question it is first required to find a total of the items that were bought. Note that the word “each” is given in bold and this is telling you that here you have to perform a multiplication.
The cost of all items bought including the cost of 2 chocolate bars can be found as follows:
\begin{array}{r} 4.50 \\ 1.35 \\ +1.10 \\ \hline 6.95 \end{array}And so the amount of change that is given is found by the following calculation:
\begin{array}{r} 10.00 \\ -\quad 6.45 \\ \hline 3.05 \end{array}Worded example question 5:
In this final GCSE maths addition and subtraction, example we are asked to complete the above bill.
First we are looking at brake cables.
You are given that 2 are purchased and the cost of each item is £5.68. So to find the total you can add £5.68 with itself or to multiply £5.68 with 2.
The cost of the brake cables = £5.68 2 = £11.36
For the pedals you are given the total cost and you know that 2 were purchased. You want to work out the cost per item. The cost per item has be smaller than the total cost so here you need to perform a division:
Cost of pedal = 45.98 \div 2=£ 22.99
For labour you are told they worked for 1.5 hours at a rate of £12 per hour.
For one hour a person is paid £12 so for 0.5 hours they will be paid £6. So the total here will be £18.
Below is the chart with all the numbers shown plus the final overall total:
The main thing to note about this question is that there are a number of various rules involved which include multiplication, division, working with a fraction as well as finding the overall total of all items.