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.
Adult model
Used tags 930−586=344, check 930−344=586. Starting cards 428+175=603, check 603−175=428. Addition or subtraction is chosen by the unknown role, not by spotting the word left.
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.
Common tangle
all left stories trigger subtraction; check the roles and equivalent quantities, rather than memorising a printed answer.
Day
57
Different guided practice
A fictional game starts with 702 tokens and ends with 459: used 243. A different game uses 126 and ends with 387: start 513. Guide both original-equation checks, one case at a time.
Check and teach the entry relationship
Contrast □ − 7 =12 with 19 − □ =12 using an empty part/whole bar. First means start 19; second means used 7. Teach small connected addition if the roles are swapped.
Hook
A missing count can sit at the start or in the amount used. Can your note make that clear?
Materials
Broad paper, labelled place-value/part-whole/number-line alternatives as suitable; optional familiar safe counters; usual communication. No hundreds of loose marks, purchases or physical handling required. Keep adult model and own work separate.
Next ordinary teaching
If all left stories trigger subtraction, teach □−4=9 by joining used 4 and left 9 into 13. Then invite □−8=15. Staff reference: starting value □=23; check 23−8=15.
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.
Partial curriculum opportunity
-
AC9M4A01
-
AC9M4N06
Purpose
Distinguish unknown starting quantity from unknown subtraction amount.
Routes
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.
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.
Id
A
Title
Small stock story
After own work: adult practice possibility
23 used; 61−23=38.
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.
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.
Id
B
Title
Two store notes
After own work: adult practice possibility
344 used tags; 603 starting cards.
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.
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.
Id
C
Title
Archive puzzles
After own work: adult practice possibility
723 removed; 2033 starting.
Session stages
Instruction
A missing count can sit at the start or in the amount used. Can your note make that clear? Read the source. Ask what the numbers count and the wanted quantity. Contrast □ − 7 =12 with 19 − □ =12 using an empty part/whole bar. First means start 19; second means used 7. Teach small connected addition if the roles are swapped.
Minutes suggestion
5
Stage
Meet the job
Instruction
Used tags 930−586=344, check 930−344=586. Starting cards 428+175=603, check 603−175=428. Addition or subtraction is chosen by the unknown role, not by spotting the word left. Show on separate adult paper. Pause after one transformation; invite explanation before showing the next.
Minutes suggestion
10
Stage
Teach one relationship
Instruction
A fictional game starts with 702 tokens and ends with 459: used 243. A different game uses 126 and ends with 387: start 513. Guide both original-equation checks, one case at a time. Offer one complete route below, not all three as a quota. Let the learner select a representation and pause or switch.
Minutes suggestion
15
Stage
Guide then choose
Instruction
Solve □ − 148 =367 and explain what the box counts. Receive an available response before staff key. If all left stories trigger subtraction, teach □−4=9 by joining used 4 and left 9 into 13. Then invite □−8=15. Staff reference: starting value □=23; check 23−8=15.
Minutes suggestion
5
Stage
Receive and choose tomorrow
What to look for
The box is the starting quantity 515; rebuilding from used 148 and left 367 supports the original equality.
After own work: staff possibility
515 starting items; 515−148=367.
Status
Proposed 35-minute shape, unpiloted and freely reorderable; resource day not school calendar requirement.
Title
Which part is missing?