Architecture of Grace
Mathematics · Number Concepts & Data

Number Concepts & Data

Concepts & Data · Activity 13 — Trade a Ten. Column subtraction with trading. Work it here, or print it and use a pencil — both count.

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Concepts & Data · Activity 13

Trade a Ten

Work one column at a time, ones first. Take away what you can — and when the top digit is too small, trade a ten from next door. Every trade gets written, just like a pencil would.

On this computer only

No score is kept. No points, no streak, no ranking — the only number anyone writes down is the one your teacher writes down, standing next to you.

  1. 1Tickets still to sell52 − 27Answer: · Write the trades over the top number
  2. 2Pages left to read73 − 46Answer: · Write the trades over the top number
  3. 3Points ahead in the game587 − 243Answer: · Write the trades over the top number
  4. 4Cans still needed435 − 218Answer: · Write the trades over the top number
  5. 5Seats still empty624 − 357Answer: · Write the trades over the top number
  6. 6Miles left to drive304 − 158Answer: · Write the trades over the top number
  7. 7Pennies left in the jar5231 − 2764Answer: · Write the trades over the top number
  8. 8People still to arrive5003 − 2867Answer: · Write the trades over the top number
How confident are you with these?

There is no right answer here. It only tells your teacher where to start next time.

For the teacher — this device only

One probe row, built from what happened on this screen. Nothing is sent anywhere — copy it into the Goal Builder yourself, or print this page. Independent means every column and every trade with no hints; supported means done after a hint. Both are real evidence and neither is a grade.

Date
—
Skill
Subtract multi-digit numbers with regrouping
Measure
Trials (x of y)
Independent
0 of 8
Supported
0 of 8
Hints used
0
Confidence
—
Watched the demo
—
Stretch
—

Items 1–2 trade once inside two-digit numbers. Item 3 needs NO trade — declining one is the skill being probed. Items 4–5 climb through three digits, item 6 trades across a zero, item 7 is a four-digit chain, and item 8 crosses zeros in the thousands (five digits in Set 3). Set 2 and Set 3 are the same skills with different numbers, so the same student can be probed three weeks running without being measured on memory.

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