# Which part is missing?


## Child direction

A missing count can sit at the start or in the amount used. Can your note make that clear? Pick one route. Show what the numbers mean, try a way, then check one result. You can stop after a useful part.

## Purpose

Distinguish unknown starting quantity from unknown subtraction amount.

## Complete fictional source

A fictional store starts with 930 tags and finishes with 586. How many were used?930−□=586. Separately, a fictional box uses 175 cards and has 428 left. How many did it start with?□−175=428.

## One own invitation

Solve □ − 148 =367 and explain what the box counts.

## Access

Show, draw, type, sign, use your usual communication or direct an agreeing helper. Choose quiet/private work, switch a route, pause, pass or finish. One useful part is enough. A helper can read the exact words or scribe your choices; supplying an operation, count, regrouping or reason is mathematical help and is named. No speed, neatness, speech, handling or device requirement.

## Routes


1. 
### Id

A

### Title

Small stock story

### Complete task

A pretend tray starts with 61 cards and ends with 38. Find how many were used.

### Entry or access

Keep start/use/left labels visible.

### Access

Show, draw, type, sign, use your usual communication or direct an agreeing helper. Choose quiet/private work, switch a route, pause, pass or finish. One useful part is enough. A helper can read the exact words or scribe your choices; supplying an operation, count, regrouping or reason is mathematical help and is named. No speed, neatness, speech, handling or device requirement.


2. 
### Id

B

### Title

Two store notes

### Complete task

Work the 930/586 tags and 175/428 cards cases separately. Name each unknown role.

### Entry or access

Do not join card and tag quantities.

### Access

Show, draw, type, sign, use your usual communication or direct an agreeing helper. Choose quiet/private work, switch a route, pause, pass or finish. One useful part is enough. A helper can read the exact words or scribe your choices; supplying an operation, count, regrouping or reason is mathematical help and is named. No speed, neatness, speech, handling or device requirement.


3. 
### Id

C

### Title

Archive puzzles

### Complete task

A fictional archive has 2001−□=1278; another has□−586=1447. Explain and check both.

### Entry or access

Offer just one equation if two cases overload the purpose.

### Access

Show, draw, type, sign, use your usual communication or direct an agreeing helper. Choose quiet/private work, switch a route, pause, pass or finish. One useful part is enough. A helper can read the exact words or scribe your choices; supplying an operation, count, regrouping or reason is mathematical help and is named. No speed, neatness, speech, handling or device requirement.