Calculating toner percentage

[f4ust]

Hello, im new to zabbix, and im trying to calculate the percentage of my printers toner (manufacturer doesnt have OIDs for percentage left). And im trying to calculate it like this
100 * ("xerox.magenta.pages.left")/("xerox.magenta.max.capacity")
and it always throws this

• Cannot evaluate expression: right operand "xerox.magenta.pages.left" is not a numeric value for operator at "* ("xerox.magenta.pages.left")/("xerox.magenta.max.capacity")"

i also tried the calculation documentation, but its too hard to understand...

[avbxl]

Could you provide some screenshots of the items "xerox.magenta.pages.left" and "xerox.magenta.max.capacity"? Also are you creating it as a dependent item or calculated item?

[f4ust]

Im creating it as an calculated item, and both max capacity and pages left are numeric values.

[f4ust]

(last(//xerox.magenta.pages.left)*100)/last(//xerox.magenta.max.capacity)

used this formula and it worked!