# Find the missing part


## Child direction

What needs to join a collection to reach the target? Pick one route. Show what the numbers mean, try a way, then check one result. You can stop after a useful part.

## Purpose

Use addition/subtraction relationships for an unknown addend.

## Complete fictional source

An invented card kit needs 725 cards in total. It already has 468. How many more are needed? 468 + □ = 725.

## One own invitation

Solve 386 + □ = 540, and show the check in the original equation.

## 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 game target

### Complete task

A made-up game target is 65 points, with 37 already recorded. Find the missing part.

### Entry or access

Use two bars for known part and unknown part.

### 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

Card kit

### Complete task

Use 468+□=725. Tell the next maker how many more cards would be needed.

### Entry or access

The future requirement is not a completed supply event.

### 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

Print target

### Complete task

An invented print target is 2400 sheets; 1587 are already counted. Find the missing part and an exact check.

### Entry or access

Choose a thousands representation only if available.

### 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.