I have problems with reading mathematical equations in which there are parentheses; could anybody help me?
- (x−a) (x+b) = 5
- (x−a) + 2 (a+10) = z
- 2 + (10−a) d = 7
- y = a/b (7c+11)
How should I read this kind of equations?
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The primary way of communicating mathematics is not oral.
If absolutely necessary, you can usually get around major problems with tone of voice, pausing and speed of pronunciation. You can sometimes add in little linguistic clues, e.g. "x minus a, all multiplied by x plus b", or "two, plus d lots of ten minus a", but most of the work is done by making sure you pronounce those commas very carefully. If you don't, you might get questions back like "wait, was that x-minus-a ... multiplied by ... x-plus-b, or x ... minus... a lots of ... x-plus-b?".
You could also go for the more literal approach of pronouncing the brackets: I've heard mathematicians say things like "bracket x minus a close bracket times bracket x plus b close bracket", but this is pretty extreme. When (the going gets tough and) the formulas get long, just write it down, say something like "x minus a times x plus b", and point. That's what everyone else does.
I have heard a few variants when it comes to reading aloud mathematical expressions involving parentheses. These include terms such as:
I do believe that the term quantity is what is used by screen-readers which are MathML compatible. The use of this term is supported to an extent in this paper (PDF). An American educational organisation also prescribes it in addition to the others:
As mentioned by Billy, pauses, speed and intonation greatly assist in avoiding confusion.
Here's how I would read the examples aloud. Commas/pauses are important to seperate the different parts.
In my university experience so far, I haven't heard math teachers read aloud the start and close parenthesis, since you usually write it down while reading it.
If you have trouble with the Maths, remember BEDMAS — Brackets, Exponents, Division, Multiplication, Addition, Subtraction. Brackets and Exponents always go one and two. Division and Multiplication are left to right so sometimes it is BEMDAS; and Adding and Subtracting are Left to Right as well so you can have BEDMSA or BEMDSA etc.
If by reading you mean reading out loud then you would say “Open brackets, x − a, close brackets. Open brackets, x + b, close brackets, equals, 5.”
It is assumed that the person listening will either write it down or make a mental picture of it, so you don’t have to say multiply the two sets together. That would be assumed. However, if you were reading to an inexperienced maths person you would say at the end “Remember you will need to multiply the two sets.”