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How come when you think of a number and times it by 2 and add ten and divide it by 2 and subtract that number it is always 5?
Wiki User
∙ 12y ago
The simplest way is to look at it algebraically.
So, suppose you start with a number. Let's call it N.
Step 1: You times it by 2. So N becomes 2*N or 2N.
Step 2: You add 10. So 2N becomes 2N + 10
Step 3: You divide by 2: So 2N + 10 becomes ("N+10)/2 which is N + 5
Step 4: You subtract the original number: So the N+5 becomes N+5-N, or 5.
Hope that's proved it for you.
Wiki User
∙ 12y ago
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If you think of a number you subtract 173 you add 369 the answer is 536 what was your number?
the number was 340
What number gives the same result when it is added five as when it is multiplied by five?
i don't think that's possible because when you add 5 to a number, it gets bigger, but when you divide a number, its always a lower number. Unless there is actually a number you can do that with but i doubt it. hey, actually, it is possible. just make an equation: 5x=5+x. you're trying to solve for x right, so subtract x from both sides. you have: 5x-x=5, the same as 4x=5. then divide both sides by five to get x=5/4. (five-fourths) yeah that's right, were smart xD
What do you get when you subtract a negative integer from a positive integer?
You will get a positive integer. If you subtract a negative number, you will be adding it. I think of it like 2 minuses equals a plus. :P
Does sold mean to add or subtract?
I think subtract.
Why is the quotient for the number divided by itself is 1?
Think of it this way...how many times can you divide a number by itself? The answer is always once. 4 divided by 4 equals 1. Using the number 4, 8 divided by 4 equals 2. In other words, 8 is equal to two 4s, right? But one 4 is always one 4.
If you subtract 19 and divide by 5 the answer is 15 what is the number?
94 i think
How do you pick a number any number and i will tell you what you end up with?
I like this one.... think of a number multiply by 2 add 12 subtract 4 divide by 2 subtract the number you thought of and the answer is 4 it always works its a mathematical certainty once you have the number 4 you can add subtract etc to your hearts content and make any new number provided you remember the answer yourself.
What is decay rate?
How fast something decomposes
When you subtract a negative number from another negative number do you get a positive or a negative number?
always a negative number. just think about going backwards on a number line.
Think of any number Add 7 to it subtract 2 Subtract your original number multiply this by 4 and subtract 2 You will always get 18 Why?
Call the unknown number n. Then, from the problem statement, {4[(n + 7 - 2) - n]} - 2 = 18. This is always true because [(n + 7 - 2) - n] is simply 5.
If you think of a number you subtract 173 you add 369 the answer is 536 what was your number?
the number was 340
What is the equation for (21)?
You can make lots of equations that have the solution 21. Here is one:x = 21If you think that is too trivial, add, subtract, multiply, or divide the same number to or from both sides.
What number do you need to subtract 100 to make 38?
think it 63
How many college athletes are there at UNC?
I think you divide the number of how many people are there there and divide it by 4....i think
What is the sum of a number and its opposite is zero?
Think about it like this. 0+x would equal x+0 but if you did the opposite then the answer would still equal x+0 because 'x' is an indefinite number and if you times, divide, subtract or plus then it would still equal x+0 or x-0 or x*0 or x divide 0.
What number gives the same result when it is added five as when it is multiplied by five?
i don't think that's possible because when you add 5 to a number, it gets bigger, but when you divide a number, its always a lower number. Unless there is actually a number you can do that with but i doubt it. hey, actually, it is possible. just make an equation: 5x=5+x. you're trying to solve for x right, so subtract x from both sides. you have: 5x-x=5, the same as 4x=5. then divide both sides by five to get x=5/4. (five-fourths) yeah that's right, were smart xD
What do you get when you subtract a negative integer from a positive integer?
You will get a positive integer. If you subtract a negative number, you will be adding it. I think of it like 2 minuses equals a plus. :P
