How to combine two equations? - Mathematics Stack Exchange
Nov 25, 2024 · You have a system of two equations. It's OK to subtract one from another and get the third equation. However, you should still have a system of two equations as the result and you …
How to add and subtract values from an average?
Feb 16, 2011 · total sum of values = 2000 + 100 mean = 2100 / 101 => 20.79 If I want to subtract a value and find out the new average: total sum of values = 2100 - 100 mean = 2000 / 100 => 20 It …
probability: when to multiply when to add? - Mathematics Stack …
Jun 12, 2020 · Therefore, you add However, if you think compounding events will decrease your chance compared to the single event, use the multiplication rule. Most of the time you will see the word AND …
How should we calculate difference between two numbers?
Aug 19, 2016 · if we are told to find the difference between 3 and 5, then we usually subtract 3 from 5 ,5-3=2 and thus, we say that the difference is 2. but why can't we subtract 5 from 3 ,3-5=...
In need of tips/suggestions when to add or multiply probabilities
38 I am having trouble deciding when to add or when to multiply probabilities as in the following example. I know that by constructing Probability tree diagrams we could multiply along branches and …
Why is that when we are adding to both sides of an equation we don't ...
Sep 27, 2018 · Lets take an example equation of $$3x - 2 = 4x +5$$ when solving this equation you would add two to both sides and get $$3x = 4x + 7$$ my question is why is that when we are adding …
Why multiply first? - Mathematics Stack Exchange
Why do we multiply/divide first, and then add/subtract later? I mean, what I'm curious about is that is this a universal rule, or a man-decided rule? Also how would you decide on which to operate ...
How to divide using addition or subtraction
Aug 25, 2012 · We can multiply $a$ and $n$ by adding $a$ a total of $n$ times. $$ n \\times a = a + a + a + \\cdots +a$$ Can we define division similarly using only addition or ...
arithmetic - What are the formal names of operands and results for ...
I'm trying to mentally summarize the names of the operands for basic operations. I've got this so far: Addition: Augend + Addend = Sum. Subtraction: Minuend - Subtrahend = Difference. Multiplicati...
Why do mathematicians use single-letter variables?
Feb 28, 2011 · And when math can use one consise letter $\Sigma$, why would it want to use sum? As for variable names themselves, I agree with most other answers in this thread.