Arrange in descending order: 1.2, 2.1, 0.12, 0.21 (Let I = 1.2, II = 2.1, III…
2023
Arrange in descending order: 1.2, 2.1, 0.12, 0.21
(Let I = 1.2, II = 2.1, III = 0.12, IV = 0.21)
- A.
IV, II, III, I
- B.
II, IV, I, III
- C.
II, I, IV, III
- D.
IV, III, I, II
Attempted by 61 students.
Show answer & explanation
Correct answer: C
Concept: To order decimal numbers, compare them place by place from the highest place value downward — first the whole-number (units) part, and only when those tie, the tenths, then the hundredths. A larger digit in a higher place makes the number larger, no matter what follows. Descending order lists the values from largest to smallest.
Application:
Compare the whole-number parts. 2.1 has units digit 2; 1.2 has units digit 1; both 0.12 and 0.21 have units digit 0. So 2.1 is the largest and 1.2 comes next.
The two values with units digit 0 are 0.21 and 0.12. Compare the tenths place: 0.21 has tenths 2, while 0.12 has tenths 1, so 0.21 is greater than 0.12.
From largest to smallest the values are 2.1, 1.2, 0.21, 0.12. In the labels of the stem that reads II, I, IV, III.
Cross-check: Read the sequence back as numbers — 2.1 > 1.2 > 0.21 > 0.12 — each value is strictly smaller than the one before, confirming a valid descending chain.