My 5th grader in New York (America/New_Y
Ask
My 5th grader in New York (America/New_York) missed these two multi-digit subtraction problems tonight:
1. 600 - 248 = 462
2. 4000 - 1375 = 3735
In both problems, whenever there was a zero on top, they just subtracted the smaller number from the larger number (like 8 - 0 = 8) instead of regrouping across zeros.
Please:
1. Cluster these into one 5-line mistake card (prompt, wrong, right, tag, cause) rather than copying them separately.
2. Set up a daily 19:00 review reminder for our timezone so we review it when it falls due.
3. Give one parallel changed-numbers problem for tomorrow's self-test.
Answer
I'll cluster this into one card (same cause: zero-regrouping), set the daily reminder in your timezone, and give you a parallel problem for tomorrow.
Let me first check what's already in the notebook and read the capture guide.
I see the notebook already has a card for this exact cause (`e4424…` due 2026-09-18: "500 − 247 = ? and 3000 − 1284 = ?"). Let me try adding the new problems and see whether the script clusters it or flags a duplicate.
Card added. Now setting up the daily 19:00 review reminder in your timezone.
You're at the cap of 20 active reminders. Let me list them so you can pick which to drop before I add this one.
Card is in (script returned `ok:true`, id `803ca0d74ab2db03`). Two things to flag before I set the reminder:
**Heads-up — same cause already covered.** A card for this same cause is already in the notebook:
- id `e4424…` (tag `subtraction-across-zeros`, cause `A2`, due **2026-09-18**)
- prompt: `500 − 247 = ? and 3000 − 1284 = ?`
So the notebook now has two cards for the same cause. That's still usable — different numbers, same fix — but if you'd rather keep one card, say the word and I'll drop the new one. New card's five lines:
| line | content |
| --- | --- |
| **Prompt** | `600 - 248 = 462 ; 4000 - 1375 = 3735` |
| **Wrong** | when 0 is on top, assumed a borrow was available (or did smaller-minus-larger like 8-0) without chaining across the zero: 600-248 came out 462, 4000-1375 came out 3735 |
| **ight** | chain the borrow across the zero first. 600 → 5 9 10, so 10-8=2, 9-4=5, 5-2=3 = **352**. 4000 → 3 9 9 10, so 10-5=5, 9-7=2, 9-3=6, 3-1=2 = **2625** |
| **Tag** | `subtraction-across-zeros` |
| **Cause** | `A2` |
**Tonight's already-due cards** (worth a quick look before bed): `1/3 + 1/4` and `400 − 167`.
**Parallel for tomorrow's self-test** (new numbers, same shape — 3-digit with one zero on top, then borrow through it):
> **700 − 358 = ?**
> Correct chain: 700 → 6 9 10 → 10−8=2, 9−5=4, 6−3=3 → **342**.
**eminder — need your call.** You're at the cap of 20 active schedules, with **8 daily-19:00 reminders already** (ids `3ec251a1`, `8a665f1b`, `a33d98ab`, `94a0833e`, `b3d77233`, `f0332b6b`, `cab23cb3`, `7e266918`). Tell me which to disable, and I'll add the new one (daily 19:00 America/New_York, prompt "eview the mistake-notebook cards due today").