Get random value in the range of plus minus 10 of a cell value in Excel

Question

I want to calculate a random value for each positive number in a column, but I want the value to be placed in a 10% range, so it can only be 10% higher or lower than the original value.

The result must be greater than zero, which is the second prerequisite.

I attempted a formula that looked like this, but it appears to be incorrect because it occasionally returns values that are lower than zero, which contradicts the second condition.

=IF(RAND()<0.5,(B2+(B2/100)*90)-(RANDBETWEEN(B2-0.1,B2+0.1)),(B2-(B2/100)*90)+(RANDBETWEEN(B2-0.1,B2+0.1)))

Answer 1

Why not just use RANDBETWEEN(B2*0.9, B2*1.1) if you are only working with integers and your value is in B2? Since 0.9 * a positive number is still a positive number, this cannot return a negative number if B2 is positive.

If you require floating point numbers, you can create a random number between 0 and 1 using the RAND() function, then divide it by 5 and remove 0.5 to get a number between -0.1 and 0.1. Then, to produce a result between 0.9 and 1.1 times the original number, add 1 and multiply that result by the original value:

=(1+(RAND()-0.5)/5)*B2