# Two-box puzzle


## A

176

## B

430

## Id

C15

## Job

equality

## Reason

Compute known side before missing part.

## Complete source

An invented equation is 176+□=400+30.

## Status

Original fictional ordinary practice; teach source/help before any own application.

## Title

Two-box puzzle

## After own work: adult practice possibility

254; 176+254=430.