Day 18 — Two full tens make twenty | Foundation Maths · T1 W3–4

25 minutes · AC9MFN01 (20 representation and 18–20 order), AC9MFN03 (count and compare 19/20); partial practice · educator review pending

Success today: The child builds 20 as two complete ten-frames, counts to verify, matches 20, and demonstrates that 20 follows 19 by one.

Prepare per pair: two ten-frames, 20 counters, cards 18–20 and 0–20 path; see print-aids.md. If using a school-approved virtual counter tool as an optional transfer, check its accessibility and privacy settings first; physical objects remain available.

Reconnect, 3 min. Show 19 with one empty space in the second ten-frame. Ask what one more will do. Let a child fill the last space.
Model, 6 min. Say, “Both frames are full. One has ten and the other has ten. I will count the whole collection to check: twenty.” Place card 20 beside it. Remove one object to show 19, replace it to show 20. Put 18, 19, 20 on the path; each step adds one object.
Play: playground plan, 9 min. Partners make 19 chalk-spot markers for a pretend plan and add one to make 20; swap. Variants: 20 star cards for an observatory display or 20 container cards for a recycling centre. Children can choose paper marks or objects, but must check the total. A virtual counter version can repeat the same task after the physical model where available.
Independent try, 4 min. Show 18, 19, 20 mixed and give 20 uncounted objects. “Show twenty and place its card after nineteen. Take one away: what number now?” Observe the child's count and reasoning.
Check and close, 3 min. Show a full first frame and a second with nine filled. “Is this nineteen or twenty? What would make twenty?” Key: 19; one more makes 20; 18, 19, 20 is the order.

If the child says 20 is two because it has two digits or frames: Count the objects in each frame, then all twenty. If a child counts ...18, 19, 30, practise the spoken 18–20 sequence with objects and path; score the object total separately from English naming when the numeral/quantity relation is shown by another response route.

Access and record: Offer a raised double frame, large/tactile whole-numeral cards, clear speech or home-language naming with the exact numeral, AAC choices and directed partner placement. Record 20-object build, card link, 19/20 one-object comparison, order and any virtual transfer separately.