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
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.
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.
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.