# Which part is missing? ## 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 1. AC9M4A01 2. AC9M4N06 ## Purpose Distinguish unknown starting quantity from unknown subtraction amount. ## Routes 1. ### 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. 2. ### 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. 3. ### 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 1. ### 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 2. ### 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 3. ### 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 4. ### 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?