# Calculator sequence without model guesswork

Subject: Deep Learning

Exam: MT2

Reader: https://deep-learning-study-room.vercel.app/#mt2/read/19/mt2-c19-s2

Canonical: https://deep-learning-study-room.vercel.app/read/dl/mt2/section/mt2-c19-s2/

The reported model name is “Casio FX ES 990”; the exact model is not confirmed. Use your calculator’s actual function labels. On common ES/ES Plus models, exp(x) is usually the shifted ln key, while the EXP/ × 10ˣ key enters scientific notation and is NOT the same as exp(x). Check the exact key labeling on your device.

For sigmoid at 2.2, type 1÷(1+exp(−2.2)). Keep the negative sign inside the exponential. Expected 0.900249511. For a negative gradient update, type old−rate × (negative gradient); use parentheses around the negative value. For cross-entropy, use −ln(probability), not log 10. For tanh, use the hyperbolic function or its exponential fraction if that function is difficult to find.

Retain 6–9 digits in intermediate results or use stored values; round final answers to 4–6 decimal places unless the paper says otherwise. Work line by line on paper even if the calculator can evaluate the whole expression. Check exp(0) = 1, ln(1) = 0, sigmoid(0) = 0.5, tanh(0) = 0 before relying on the chosen key sequence.