why use brackets in mathematical calculations?

Question

I need to explain to some Year 4 children (age 8-9) why brackets are used, any simple terms would be grateful!

Answer 1

Simply to group terms. Parentheses are used as well.

Example: If one wanted to multiply x + y by 2, this could be how it is displayed 2[x + y] or 2(x + y)
.

Answer 2

If more than one operation is to be carried out, it is important to know which one should be done first. The answer may be different if you carry out the operations in another order! For example, in the following expression no brackets have been used and it is ambiguous.

2 x 3^2

Either we could multiply 2 by 3 and then square the result, or we could square 3 first and then multiply the result by 2. The first calculation would give the answer 36, while the second calculation would give 18. By using brackets we can specify which operation is to be carried out first.

(2 x 3)^2

and

2 x (3^2).

The rule is: we must always carry out the operation in brackets first.

Answer 3

brackets are used to indicate that the quantities between the brackets need to be computed before a computation takes place outside the brackets.
hence: 4 x [6 + 3 + .5 ]. first add the 6, 3 & .5 together and then multiply the result by 4.

Answer 4

Mathematics consists of a sequence/combination of calculations which have to be carried out in a logical manner

When a problem is presented in 'English' the different parts of the data provided are identifiable by use of commas, colons or, indeed, brackets.

When all of the given information is 'inserted' into a known mathematical expression or formed into calculation the separate sets of data are kept separate by use of brackets [], {}, or () or sometimes more.

The Golden Rule of the sequence of calculating Combined calculations is B O D M A S

Brackets
Of (Powers)
Division
Multiplication
Addition
Subtraction

This reminds us that Calculations within ALL brackets are done First

etc etc...

hope this helps :-)

Answer 5

brackets are used to show you that you need to do that part of the equation and then use the answer in the bracket for the rest of the problem
ie: {(6-5) + (3+8)} - 2 = ?
do the () first then the {} then minus the 2

Answer 6

I would simply give an example.

John had 3 pencils and gave one to Mary. Next day Mary returned to John as many penciles as he had left.

First try solving this without using paper, the child will calculate the right answer, which is for.

Then try to write this down.
(3-1)*2=2*2=4.

Try to do this without brackets, you get
3-1*2=3-2=1 which is wrong!

Answer 7

you use them when you need to override the correct order of operations. For example, if you see 5+6*2, you are supposed to perform the multiplication first, then the addition (regardless of the order). But if you really meant to add 5+6 first, then multiply the result by 2, you would have to enclose the sum in brackets to say "Do this first no matter what the order of operations tells you to do!" (5+6)*2

By the way, many children are taught PEMDAS --> "Please exuse my dear Aunt Sally", a mnemonic device for remembering

Parentheses
Exponents
Multiplication
Division
Addition
Subtraction

Answer 8

The brackets are helpful! They tell you which bits to do first.
Work out the bits in the brackets before you work out the rest of the sum.

Answer 9

ha- too consumer-friendly all and sundry else is powerful, yet sick clarify it marvelous an consumer-friendly BODMAS- Brackets of branch, Multiplication, Addition, Subtraction. the order of maths. Brackets first. (40+20)=60, (30+10)=40. then branch. 40/2= 20. final, multiplication. 60 x 20= 1200 too consumer-friendly.

Answer 10

They determine which calculations must be done first.
2x+y will give you a different result than 2(x+y). In the first equation, you would multiply x by 2, then add y. In the second, you would add x and y first, then multiply the result by 2.