Exercise · L3

Sign-switch relay

mixed-operations mixed-sequence 8 min 数二七五

L3Level

mixed-operationsSkill

mixed-sequenceType

8mTime

Best for

Best for focused single-question practice and careful method review.

Practice rule: try this before opening the hint or answer.

Solve 274 + 18 - 39 + 22 and protect the total at each sign change.

Reusable visual engine

Visual support for Sign-switch relay

Value 275 · 二七五

Step 1

275

Step 2

274

Step 3

292

Step 4

253

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