Class D operator math, solved with you step by step
Been out of school a while? Forgot the basics after years on the job? That is completely normal, and it is exactly who this is for. We hold your hand through every single step so you never stare at a problem and go blank.
- Try it on paper first
- Hints one at a time
- Every step explained, no gaps
- A trick so it sticks for good
Pick your exam
Or pick a topic
Every problem, by topic
Volume and gallons
Open topic →- Water & wastewaterHow many gallons are in a 20 by 10 by 8 foot tank?
- WaterHow many gallons are in a 30 foot round tank?
- Water & wastewaterHow many gallons are in 2,000 cubic feet?
- WaterHow many gallons are in a 12 foot round tank, 10 feet deep?
- WaterHow many gallons are in 1,000 feet of 6 inch main?
- WaterHow many gallons are in 800 feet of 12 inch main?
- WaterHow many gallons are in 500 feet of 24 inch main?
- WaterHow many gallons are in 2,000 feet of 8 inch main?
Area
Open topic →- Water & wastewaterWhat is the area of a 40 by 12 foot clarifier?
- Water & wastewaterWhat is the area of a 20 foot round clarifier?
- Water & wastewaterWhat is the area of a 30 by 15 foot basin?
- Water & wastewaterWhat is the area of a 25 foot round tank?
- Water & wastewaterWhat is the area of a 50 by 20 foot basin?
Dosage and pounds
Open topic →- Water & wastewaterHow many pounds of chlorine for 2 MGD at 3 mg/L?
- Water & wastewaterHow much does 500 gallons of water weigh?
- Water & wastewaterHow many pounds of chlorine for 0.5 MGD at 2 mg/L?
- WaterHow many pounds of alum for 3 MGD at 12 mg/L?
- WaterHow many pounds of chlorine to disinfect a 12,000 gallon main?
Flow and conversions
Open topic →- Water & wastewaterHow do you turn 350 GPM into gallons per day?
- Water & wastewaterWhat is the flow if 6,000 gallons fill in 30 minutes?
- Water & wastewaterHow many GPM is 1.44 MGD?
- Water & wastewaterHow do you turn 720,000 GPD into MGD?
- Water & wastewaterHow many GPD is 1,000 GPM?
- Water & wastewaterWhat is the flow if 12,000 gallons fill in 40 minutes?
Detention time
Open topic →Percents
Open topic →- WastewaterWhat percent of the BOD was removed?
- Water & wastewaterWhat percent of capacity is 400 GPM out of 500?
- WastewaterWhat percent of the TSS was removed, 240 to 60?
- WastewaterWhat percent of the BOD was removed, 180 to 36?
- WaterWhat percent of the water is lost if 500,000 is pumped and 450,000 delivered?
If any of this sounds like you, you are in the right place
These are the honest worries operators run into most. None of them mean you cannot do it.
“I have been out of school for years and forgot the math.”
That is exactly who this is built for. Every step is written out and explained like you are brand new, so nothing is assumed and nothing is skipped.
“It is closed-book. I will blank on the formulas.”
You are given a formula and conversion sheet at the exam. You do not memorize numbers, you learn when to reach for them. We show you exactly that.
See the formula reference →“I am just not a math person.”
Operator math is a small set of the same steps repeated. Learn a handful of patterns and you have most of it. We hand you a memory trick for each one.
See the math, solved simply →“There is so much. I do not know what is even tested.”
We stick to the exact Texas Class D scope, nothing from a higher grade, nothing padded. Less to study, and all of it counts.
What is on the exam →Preparing for the whole exam?
The full Texas Class D prep, when you are ready
These worked problems are free. When you want the full picture, the reviewed question bank covers every Class D subject, with a guided study path, drills, and a timed practice exam.
- Reviewed questions for every Class D subject
- A guided study path that tells you what to do next
- A timed practice exam that mirrors the real format
- Operator math worked step by step, with calculators
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