Ensure unique solutions to random formula

C

Clayman

I am developing a math lesson worksheet for my homeschool lessons. One way
it's working quite well is to use the solutions of problems to find a letter
code. I would like to have the following attributes:
1.) 26 randomly-generated math problems, each with a unique solution.
2.) Not write a bunch of VB code to do it. (I'm kinda burned out on that).

Is there an easy solution? If you would like to see what I have so far,
please request it and I'll e-mail it to you. There is no VB on it right now,
so you can open it with macros turned off.
 
B

Bernie Deitrick

Clay,

What kind of math problems are you looking at creating?

You could use sets of formulas like this, to create a division problem in cell D1:
Cell A1 =ROUND(RAND()*12,0)
Cell B1 =ROUND(RAND()*12,0)
Cell C1 =A1*B1
Cell D1 = C1 & " / " &B1 &" = ?"

Each press of F9 will create a new division problem, selected from up to the 12 times tables.

HTH,
Bernie
MS Excel MVP
 
B

Bernie Deitrick

Clay,

If you aren't at the level that you're teaching that any number / 0 is undefined, then use this in
Cell B1

= 1 + ROUND(RAND()*11,0)

HTH,
Bernie
MS Excel MVP


Bernie Deitrick said:
Clay,

What kind of math problems are you looking at creating?

You could use sets of formulas like this, to create a division problem in cell D1:
Cell A1 =ROUND(RAND()*12,0)
Cell B1 =ROUND(RAND()*12,0)
Cell C1 =A1*B1
Cell D1 = C1 & " / " &B1 &" = ?"

Each press of F9 will create a new division problem, selected from up to the 12 times tables.

HTH,
Bernie
MS Excel MVP
Click to expand...
 
C

Clayman

Yeah, I've got that down. Actually, we're working only with add & subtract
right now. I've got random number generators (that will automagically put the
bigger number on top). But I want the solutions to be unique. The solutions
point to letters in the alphabet, to solve a riddle.
--
Adios,
Clay Harryman


Bernie Deitrick said:
Clay,

If you aren't at the level that you're teaching that any number / 0 is undefined, then use this in
Cell B1

= 1 + ROUND(RAND()*11,0)

HTH,
Bernie
MS Excel MVP
Click to expand...
 
C

Clayman

Thank you for the quick answer, though! That was much quicker than I
anticipated!
--
Adios,
Clay Harryman


Bernie Deitrick said:
Clay,

If you aren't at the level that you're teaching that any number / 0 is undefined, then use this in
Cell B1

= 1 + ROUND(RAND()*11,0)

HTH,
Bernie
MS Excel MVP
Click to expand...
 
B

Bernie Deitrick

Clay,

OK, I think I understand now. I always liked those problems when my kids
were that age.

Anyway, try this:

Cells A1:A100 =ROUND(RAND()*100,0)
Cells B1:B100 =IF(COUNTIF($A$1:$A$100,A1)=1,"OK","Not")
Array enter, using Ctrl-Shift-Enter, in Cells C1:C26:
=INDEX(A:A,LARGE(ROW($B$1:$B$100)*($B$1:$B$100="OK"),ROW()))

Cells D1:D26 A through Z
Cells E1:E26 =RAND()
Cells F1:F26 =INDEX($C$1:$C$26,RANK(E1,$E$1:$E$26))

When you press F9, you will get a unique list of 26 random numbers between 1
and 100 in cells F1:F26, each corresponding to a letter A through Z.

Modify the formulas in A1:A100 to change your range of numbers.

HTH,
Bernie
MS Excel MVP
 
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