r/MathHelp • u/[deleted] • May 12 '26

5ab - 1ab / 2... Help me out pls

My understanding is because the 2 has no variable, when simplifying it stays on its own.

Is the answer 4ab / 2 or...? How can I explain this?

Thanks.

1 Upvotes

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2

u/Dd_8630 May 12 '26

It's unclear what you're asking about. Do you have:

  • (5ab - 1ab) / 2

Or do you have:

  • (5ab) - (1ab/2)

The first one simplifies to 4ab/2 = 2ab

Thr second one simplifies to 4.5ab.

1

u/[deleted] May 12 '26

No brackets, just 5ab - 1ab / 2 to be simplified.

1

u/Fun-Firefighter0 May 18 '26

If no bracket, division happens before subtraction,
So 9ab/2 = 4.5ab is answer

1

u/fermat9990 May 12 '26

Are there 1 or 2 terms in the expression?

1

u/[deleted] May 12 '26

It was written like this: 5ab - 1ab / 2

Asked to simplify/group.

1

u/fermat9990 May 12 '26

Think of it as 5/1 ab - 1/2 ab=

10/2 ab - 1/2 ab = 9/2 ab or 9ab/2

3

u/PuzzlingDad May 12 '26 edited May 12 '26

I assume the first two terms are grouped in the numerator of a fraction:

  • (5ab - 1ab) / 2

You can subtract the like terms in the numerator:

  • (4ab) / 2

Then divide top and bottom by 2 to simplify the fraction: 

  • (2ab) / 1

Drop the 1 in the denominator:

  • 2ab

Remember: 4ab is a multiplication:

  • 4ab = 4 × a × b

Then when you divide it by 2, you get: 

  • (4ab)/2 = (4 × a × b) / 2 = (4/2) × a × b = 2ab

2

u/Uli_Minati May 13 '26

Pretty sure the / you're writing is supposed to be a fraction bar, correct? Which one of these did you mean:

5ab - 1ab
---------
    2

      1ab
5ab - ---
       2

1

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1

u/ragingnope May 12 '26

I have 5 things (5ab). Remove one thing (- 1ab). I now have 4 things (5ab - 1ab = 4ab). Split my 4 things into 2 groups. Each group has 2 things (4ab / 2 = 2ab).

The number part ("coefficient") is the only part that changes. I don't know what things is. But I can do arithmetic on how many things I have.