Mistake notebook: 32 questions answered by the AI assistant

Mistake notebook: questions in English answered by the Doramagic.ai AI assistant, newest first.

  1. My 6th grader made the exact same mistak
    2026-09-25 · Mistake notebook

    My 6th grader made the exact same mistake on two fraction division homework problems tonight: Problem: (2/3) ÷ (4/5) Student wrote: (3/2) × (4/5) = 12/10 = 6/5

  2. My 8th grade daughter keeps making this
    2026-09-23 · Mistake notebook

    My 8th grade daughter keeps making this error on algebra tests: When evaluating -4^2, she writes +16. When evaluating -5^2, she writes +25. She reasons: "A nega

  3. My 5th grader consistently makes this de
    2026-09-23 · Mistake notebook

    My 5th grader consistently makes this decimal multiplication error: when computing 0.4 × 0.3, she multiplies 4 × 3 = 12 correctly, then writes 1.2 instead of 0.

  4. My 7th grader keeps making the same alge
    2026-09-22 · Mistake notebook

    My 7th grader keeps making the same algebra error: given x + 5 = 12, she writes x = 12 + 5 = 17. She knows to "move the 5 to the other side" but doesn't flip th

  5. My 8th grader keeps making the same perc
    2026-09-21 · Mistake notebook

    My 8th grader keeps making the same percent-increase error: given "find 20% increase on $80," she writes $80 + 20 = $100 instead of $80 × 1.20 = $96. She's trea

  6. My son is in 7th grade and keeps making
    2026-09-21 · Mistake notebook

    My son is in 7th grade and keeps making the same mistake on negative number subtraction: he writes −3 − (−5) = −8 every time. He's treating "minus a negative" a

  7. My 8th grader made this error on tonight
    2026-09-19 · Mistake notebook

    My 8th grader made this error on tonight's geometry homework: Problem: ight triangle with one leg a = 6 and hypotenuse c = 10. Find the length of unknown leg b.

  8. Please log this mistake into my daughter
    2026-09-19 · Mistake notebook

    Please log this mistake into my daughter's mistake notebook: Problem: Calculate 3/4 ÷ 2/5. Her wrong answer: She flipped the dividend instead of the divisor and

  9. Please log this mistake into my daughter
    2026-09-19 · Mistake notebook

    Please log this mistake into my daughter's mistake notebook: Problem: In triangle ABC, AD bisects angle BAC with D on BC. Given AB=12, AC=8, BC=15, find BD. Her

  10. My 8th-grade daughter is working on syst
    2026-09-18 · Mistake notebook

    My 8th-grade daughter is working on systems of equations tonight. In the problem: Equation 1: 2x + 3y = 12 Equation 2: 2x - 5y = -4 She subtracted Equation 2 fr

  11. We live in Chicago, IL. My 7th grader br
    2026-09-18 · Mistake notebook

    We live in Chicago, IL. My 7th grader brought home his physical science worksheet tonight with 2 missed questions on chemical reactions: Question: "What happens

  12. My 6th-grade son had a fraction arithmet
    2026-09-18 · Mistake notebook

    My 6th-grade son had a fraction arithmetic quiz yesterday in Chicago, IL (America/Chicago timezone). He got four division problems wrong because of the exact sa

  13. My 7th grader brought home his introduct
    2026-09-18 · Mistake notebook

    My 7th grader brought home his introductory algebra worksheet tonight with these two errors marked wrong: 1) Simplify 3x + 5 -> He wrote 8x 2) Simplify 4a + 2b

  14. My 6th grader got several problems wrong
    2026-09-17 · Mistake notebook

    My 6th grader got several problems wrong on today's math worksheet: For converting 1/5 to a decimal, he wrote 0.5 (instead of 0.2). For converting 1/4 to a deci

  15. My 6th-grade daughter made the exact sam
    2026-09-17 · Mistake notebook

    My 6th-grade daughter made the exact same error on three problems on her math quiz: Convert 6% to a decimal -> she wrote 0.6 (instead of 0.06) Convert 4% to a d

  16. My 5th-grade son is practicing decimal a
    2026-09-17 · Mistake notebook

    My 5th-grade son is practicing decimal addition and made the exact same alignment error across three problems on his worksheet: 3.5 + 0.48 = 0.83 (he aligned 5

  17. My 6th-grade daughter is practicing basi
    2026-09-17 · Mistake notebook

    My 6th-grade daughter is practicing basic integer arithmetic and made the exact same sign error across three problems: 5 - (-3) = 2 (she calculated 5 - 3) -4 -

  18. My 6th grader made the exact same mistak
    2026-09-16 · Mistake notebook

    My 6th grader made the exact same mistake on two quiz problems tonight: 1) Problem: Evaluate 3^4. Student wrote: 12 (calculated 3 * 4). Correct answer: 81 (3 *

  19. My 4th grader made these two errors on t
    2026-09-16 · Mistake notebook

    My 4th grader made these two errors on tonight's geometry homework: 'Find perimeter of an 8m by 5m garden' -> wrote 40 m (did 8 × 5). 'Find perimeter of a 10in

  20. My 5th grader repeatedly makes this erro
    2026-09-16 · Mistake notebook

    My 5th grader repeatedly makes this error when multiplying decimals: 1) 3.2 × 0.4 = 12.8 (counted only 1 decimal place instead of 1+1=2) 2) 1.5 × 0.03 = 0.45 (c

  21. My 6th grader repeatedly makes this mist
    2026-09-16 · Mistake notebook

    My 6th grader repeatedly makes this mistake when dividing fractions on homework: 1) 2/3 ÷ 4/5 = (2*4)/(3*5) = 8/15 (she multiplied straight across instead of mu

  22. My 5th grader in New York (America/New_Y
    2026-09-16 · Mistake notebook

    My 5th grader in New York (America/New_York) missed these two multi-digit subtraction problems tonight: 600 - 248 = 462 4000 - 1375 = 3735 In both problems, whe

  23. We live in New York, NY (America/New_Yor
    2026-09-16 · Mistake notebook

    We live in New York, NY (America/New_York). My 5th grader made these two errors on his homework tonight: 500 - 247 = 363 (subtraction across zeros error). 3000

  24. We live in Los Angeles, California (Amer
    2026-09-16 · Mistake notebook

    We live in Los Angeles, California (America/Los_Angeles). My 6th grader made these two errors on his homework tonight: 1/3 + 1/4 = 2/7 (he added the top numbers

  25. We live in New York (America/New_York).
    2026-09-16 · Mistake notebook

    We live in New York (America/New_York). My 6th grader made these two errors on his homework tonight: 8 - 2 × 3 = 18 (he calculated 8 - 2 = 6 first, then 6 × 3 =

  26. We live in New York (America/New_York).
    2026-09-16 · Mistake notebook

    We live in New York (America/New_York). My 8th grader was doing homework on linear inequalities. Problem 1: -2x < 6, he wrote x < -3 (correct is x > -3). Proble

  27. We live in New York, USA. My 7th grade s
    2026-09-16 · Mistake notebook

    We live in New York, USA. My 7th grade son just got his pre-algebra homework back with three marked errors: -3(2x - 5) => he wrote -6x - 15 -(4a - 7) => he wrot

  28. We live in Denver, Colorado (Mountain Ti
    2026-09-16 · Mistake notebook

    We live in Denver, Colorado (Mountain Time, America/Denver). My 6th grade son is working on fraction division. On his quiz last Friday, he missed 8 problems, bu

  29. I am sitting with my 8th grader tonight
    2026-09-16 · Mistake notebook

    I am sitting with my 8th grader tonight reviewing her pre-algebra / algebra 1 worksheet in Denver, Colorado (America/Denver). She missed 6 problems on the page,

  30. My 5th grade son keeps making the exact
    2026-09-16 · Mistake notebook

    My 5th grade son keeps making the exact same error across his entire fraction homework sheet: 1) 1/3 + 1/4 = 2/7 (he added numerators 1+1=2 and denominators 3+4

  31. My 7th-grade son spends 4 agonizing hour
    2026-09-16 · Mistake notebook

    My 7th-grade son spends 4 agonizing hours every Sunday writing test corrections. His teacher makes them copy out every missed test problem into a notebook, writ

  32. My 5th grader keeps repeating these two
    2026-09-15 · Mistake notebook

    My 5th grader keeps repeating these two mistakes on his homework every week: 1) Adding fractions: 1/3 + 1/4 = 2/7 (he just adds the numerators and denominators