Problem 3 · 1989 AJHSME
Easy
Fractions, Decimals & Percents
compare-decimals
Which of the following numbers is the largest?
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Answer: A — .99.
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Hint 1 of 3
Every choice starts with .9, so the tenths place is a tie. Where do the numbers first disagree?
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Hint 2 of 3
Compare decimals column by column from the left, like comparing words in a dictionary — the first place they differ decides it. Length does NOT decide it.
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Hint 3 of 3
Look at the hundredths place (second digit after the point): which choice has the biggest digit there?
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Approach: compare left-to-right, first difference wins
- All five share .9 in the tenths place, so that round is a tie. Move to the next column — the hundredths. There .99 shows a 9 while every other choice shows a 0.
- A bigger digit in the first column that differs settles it immediately, so .99 is largest.
- Trap to avoid: more digits does NOT mean bigger. .9099 looks long but .9 then 0 makes it smaller than .99 right at the hundredths column. Lining the decimal points up vertically makes this obvious.
Mark:
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