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150 multiple-choice questions, 75 flashcards and 10 scenario simulations, written to the Common Core State Standards blueprint. Every question carries a full rationale.
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Common Core State Standards (CCSS) — Mathematics, Grade 4: Number & Operations in Base Ten (4.NBT.A.1-3, 4.NBT.B.4-6). Public standards from corestandards.org.
CoStudy's 4th Math: Number & Operations Base Ten bank holds 235 items. Every multiple-choice question carries a written rationale explaining why the correct answer is correct and why each distractor is tempting but wrong, and the bank includes 10 scenario-based simulations.
A sample of 12 multiple-choice questions from the bank, with the full rationale shown.
Write 'six thousand three hundred forty-five' in standard form.
Answer: D — 6,345
6,000 + 300 + 40 + 5 = 6,345. (B),(C),(A) wrong order.
Which number equals 30,000 + 4,000 + 200 + 5?
Answer: D — 34,205
D) Correct. B) tens vs hundreds swapped. C) missing 10k. A) extra place.
100,000 − 1 = ?
Answer: D — 99,999
D) Correct. B/C/A) wrong.
864 ÷ 4 = ?
Answer: D — 216
D) Correct. B/C/A) miscount.
5,400 ÷ 6 = ?
Answer: A — 900
A) Correct. B/C/D) miscount.
850 cookies are packed in 6 boxes equally. How many per box?
Answer: B — 141 r 4
6 × 141 = 846, remainder 4. (A) drops remainder; (C),(D) wrong.
A city's population changed from 254,876 to 289,013. Increase?
Answer: D — 34,137
D) Correct. B/C/A) miscount.
2,340 ÷ 4 = ?
Answer: A — 585
A) Correct. B/C/D) miscount.
567 ÷ 7. Quotient and remainder?
Answer: A — 81 r 0
7 × 81 = 567 exactly. (B),(C),(D) wrong.
Round 78,499 to nearest thousand.
Answer: C — 78,000
C) Correct — 499 < 500. B) rounded up. C/D) wrong place.
780 ÷ 5 = ?
Answer: D — 156
D) Correct. B/C/A) miscount.
9,001 − 4,678 = ?
Answer: D — 4,323
D) Correct. B/C/A) miscount.
6 sample cards from the 75 in the bank.
What is 50 × 60?
3,000.
What is 12,345 + 8,765?
21,110.
What does '10 times' mean for place value?
Each place is 10 times the place to its right. The 4 in 4,000 is 10× the 4 in 400.
What is 12 × 1000?
12,000.
Round 67,892 to the nearest ten-thousand.
70,000. (Thousands digit 7 → round up.)
Word: 432 candies split into 9 equal bags. How many per bag?
48. 432 ÷ 9 = 48.
These samples are a small slice. The full bank runs flashcards, multiple choice and timed mock exams with per-chapter progress tracking, on the web and in the iOS app.
Open 4th Math: Number & Operations Base Ten →
The 4th Math: Number & Operations Base Ten bank holds 235 items: 150 multiple-choice questions, 75 flashcards and 10 scenario-based simulations. 18 of them are on this page to read free, with no signup.
Yes. Every multiple-choice item carries a written rationale that states the controlling principle behind the correct answer and then addresses each wrong option in turn — why it tempts and precisely where it fails. Knowing why the plausible answer was wrong is worth more than knowing which letter was right.
Common Core State Standards (CCSS) — Mathematics, Grade 4: Number & Operations in Base Ten (4.NBT.A.1-3, 4.NBT.B.4-6). Public standards from corestandards.org.
The samples on this page are free to read in full, rationales included, with no account. The complete 235-item bank, the timed mock exams and per-chapter progress tracking are part of CoStudy on the web and in the iOS app.
Last reviewed 2026-08-22. Banks are written against the certifying body's published exam outline and re-checked when that outline changes — exams get renumbered, retired and reweighted, and a bank written to a superseded outline teaches the wrong proportions. Figures that are re-indexed annually are deliberately not asserted as rules; the questions test the governing principle instead.