# A complete arithmetic calculation

Subject: Deep Learning

Exam: TEE

Reader: https://deep-learning-study-room.vercel.app/#tee/read/2/tee-c2-s8

Canonical: https://deep-learning-study-room.vercel.app/read/dl/tee/section/tee-c2-s8/

Evaluate 0.4 − 0.1 × (−2). The multiplication has priority over the subtraction.

![The negative product stays in brackets until the final subtraction is simplified.](https://deep-learning-study-room.vercel.app/assets/figures/v_arithmetic.svg)

Diagram: The negative product stays in brackets until the final subtraction is simplified.. Labels: Carry a negative result as one bracketed value | Carry a negative result as one bracketed value | Example: 0.4 − 0.1 × (−2). | Multiply first | 0.1 × (−2) = −0.2 | Replace product | 0.4 − (−0.2) | Subtract negative | 0.4 + 0.2 = 0.6 | The two minus signs have separate jobs before they simplify.

The negative product stays in brackets until the final subtraction is simplified. Tap the diagram to enlarge.

**Step 1:** multiply 0.1 by −2, giving −0.2.

**Step 2:** substitute that entire result, including its sign: 0.4 − (−0.2).

**Step 3:** subtracting a negative means adding its positive value: 0.4 + 0.2 = 0.6.

The answer is **0.6**. This calculation will later appear inside a weight update; the arithmetic is exactly the same.