# The missing refill


## Complete neutral source

A fictional kit needs 725 labels in total. It has 468 labels available. Find the further labels needed: 468+□=725. The box stands for a whole-number value. No real refill is supplied.

## Eligibility

After unknown addend, part/whole and substitution have been taught, e.g. Day 56. No assumed mastery from resource-week labels.

## Access and help

Read or sign the exact source and prompts neutrally, enlarge them, or scribe the learner’s chosen words. A figure, operation, regrouping, equation role or check supplied by an adult is mathematical help and is recorded as such. Show, draw, type, sign or use usual communication. One component can be enough; pause/pass/finish are choices. Four own spaces are genuinely empty. Models, criteria and next lessons stay on separate staff pages.

## First later limit

First/later are opportunity labels, not fixed order, matches, calibrated difficulty or learning gain. If source/answer exposed, record that rather than claim unseen.

## Prompts


1. What does the box count? Describe the known part and the whole.

2. Find a value for the box with a useful strategy.

3. Put your value into the original equation and check it.

4. A fictional note says “the box is 725 because that is the answer after the equals sign”. Keep or repair it with a reason.