The practice engine
Practice drills
Every problem is generated from a seed and graded exactly, with the worked solution shown after each answer. The mixed drill below rotates all six skills and leans toward the ones you have missed recently; each tool page also carries a single-skill drill. Progress is stored in your browser only.
Mixed drill: all six skills
Unlimited generated problems with exact answers and worked steps. Skills you miss recently appear more often.
Your mastery
Accuracy, streaks, and daily counts live in this browser. Clearing site data resets them.
Progress analytics
Overall: 0/0 correct
| Skill | Attempts | Accuracy | Streak | Best | Last 10 |
|---|---|---|---|---|---|
| Rx transposition | 0 | - | 0 | 0 | - |
| Prentice's rule | 0 | - | 0 | 0 | - |
| Vertex compensation | 0 | - | 0 | 0 | - |
| Minimum blank size | 0 | - | 0 | 0 | - |
| Meridian power | 0 | - | 0 | 0 | - |
| Vertical imbalance | 0 | - | 0 | 0 | - |
Drill a single skill
Transposition, Prentice's rule, vertex compensation, blank size, meridian power, and vertical imbalance each pair their calculator with a dedicated drill.
Frequently asked questions
How do the practice drills work?
Each drill is generated from a seed, so problems never repeat from a fixed bank and every answer is computed exactly with a step-by-step worked solution. Type your answers and check them; misses lower a skill's mastery and make that skill appear more often.
What is exam mode?
A timed run with a configurable question count and clock across all six skills, scored at the end. Untimed drills are always available; the timer is the exam-pressure add-on.
Is my progress uploaded?
No. Mastery, streaks, and daily counts are stored in your browser only. Clearing site data resets them.