I have four tables.

Compounds

Treatments

Treatments_Compounds Join

Weight

The weight record is a related weight (grams).

Treatments is just a table that records the event

Compounds have information about them including the appropriate formula that has one variable that needs replaced, current weight.

An example is x/20*100 were i need to replace x. I tried the Let fx but couldn't get a number result. Can anyone help

Thanks

M

This is not very clear. If the formula is text to begin with, replacing "x" with another value will result in a new text string. You can then use the Evaluate() function to get the result of the formula - provided it's valid Filemaker syntax.

Sorry Comment,

Let me try again

I weigh a subject to get the current weight so I can apply a correct dose.

Right now I have to figure out the basic calc on paper so the user has to multiply the weight by some final number. What I would like is for the user to insert the formula

X= Current Weight

X*((50/100)/1000)^2

How can I get this to result in a number rather than just the text.

Note...all are number fields. Is this wrong?

Units are applied later using a separate field.

Why dont you have two fields for your formula.

weight and formula. Weight will be a number and formula will be text. Your users will type in the weight amount and the formula that they want to use at that time.

Then the calc with num result could be weight * Evaluate ( formula )

Or:

Evaluate ( Substitute ( Formula ; "x" ; Weight ) )

The user inputs the measured weight into the Weight field (Number), and the formula into the Formula field (must be Text). The result of the calculation can be a Number.