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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 5: Number & Operations in Base Ten (5.NBT.A.1-4, 5.NBT.B.5-7). Public standards from corestandards.org.
CoStudy's 5th 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.
What is 1,728 ÷ 12?
Answer: D — 144
12 × 144 = 1728. (B),(C),(A) miscalculate.
A gallon of paint costs $19.95. 3 gallons?
Answer: A — $59.85
A) Correct — 19.95×3. B) rounded. C/D) wrong.
Value of the 5 in 12.345?
Answer: A — 0.005
A) Correct — thousandths. B/C/D) wrong.
9.05 − 4.28 = ?
Answer: B — 4.77
B) Correct — borrow across decimal. B/C/D) miscount.
In 42.678, the 8 is in which place?
Answer: C — Thousandths
C) Correct. B) 7. A) 6. D) 2.
236 × 14 = ?
Answer: D — 3,304
D) Correct. B/C/A) miscount.
Which expanded form is 5.073?
Answer: A — 5 + 0.07 + 0.003
5 ones + 0 tenths + 7 hundredths + 3 thousandths. (B),(C),(D) wrong places.
5 kids share $6.25 equally. How much each?
Answer: D — $1.25
6.25 ÷ 5 = 1.25. (B),(C),(A) miscalculate.
$45.00 ÷ 4 = ?
Answer: A — $11.25
A) Correct. B/C/D) miscount.
0.03 × 6 = ?
Answer: D — 0.18
D) Correct. B/C/A) wrong.
85 × 60 = ?
Answer: C — 5,100
C) Correct. B/C/D) miscount.
When multiplying decimals, count decimal places in:
Answer: A — Both factors, sum in product
A) Correct. B/C/D) wrong.
6 sample cards from the 75 in the bank.
What is 478 × 23?
10,994.
Round 12.84 to the nearest whole number.
13.
Round 9.95 to the nearest tenth.
10.0. (Tenths 9 + round up = 10 in the ones; tenths becomes 0.)
What is 8.0 − 3.45?
4.55.
What place is the second digit after the decimal point?
Hundredths.
Compare 3.456 and 3.465. Which is greater?
3.465. Same to tenths; compare hundredths: 6 > 5.
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 5th Math: Number & Operations Base Ten →
The 5th 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 5: Number & Operations in Base Ten (5.NBT.A.1-4, 5.NBT.B.5-7). 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.