Read the door math before it reads you

Every stage repeats the same useful question: what will each door do to the age I have right now?

The repeatable loop

1

Read

Check both operators and numbers.

2

Calculate

Apply each result to your current age.

3

Choose

Prefer the result that protects the run.

4

Climb

Move to the next stage and repeat.

The four confirmed door families

+N

Addition

Adds the shown value to your current age.

Usually predictable; risk rises near the upper range.
−N

Reduction

Subtracts the shown value from your age.

A recovery tool when you are approaching or inside Too Old.
×N

Multiplier

Multiplies your current age.

Low impact early, high impact late. Verified examples include x2 and x3.
?

Mystery

Hides the result until you commit.

Uncertain by design; compare it with the visible alternative.

Why the same door changes value over a run

AGE 8

× 2 = 16Still comfortably low

AGE 67

× 2 = 134Current footage marks 134 as Too Old

The operator is only half the decision. Always combine it with your current age. That is why a multiplier can be harmless early and costly late.