Question

what is 89.91 rounded to the nearest tenth?

Explanation:

Step1: Identify the tenths and hundredths place

The number is 89.91. The tenths place digit is 9 (after the decimal, first digit) and the hundredths place digit is 1 (after the decimal, second digit).

Step2: Apply rounding rule

To round to the nearest tenth, we look at the hundredths place. If the digit in the hundredths place is less than 5, we keep the tenths place digit as it is; if it's 5 or more, we round up the tenths place digit. Here, the hundredths place digit is 1, which is less than 5. But wait, 89.91: the tenths digit is 9, and hundredths is 1. Wait, no, wait: 89.91. Let's re - check. The number is 89.91. The tenths place is 9 (the first digit after decimal), hundredths is 1 (second digit after decimal). Wait, but when rounding to the nearest tenth, we look at the hundredths digit. Since 1 < 5, we don't round up the tenths digit? Wait, no, wait, 89.91. Wait, maybe I made a mistake. Wait, 89.91: the tenths place is 9, and the number after tenths is 1. Wait, no, the rule is: for a number \(a.bc\) (where \(a\) is the integer part, \(b\) is the tenths digit, \(c\) is the hundredths digit), to round to the nearest tenth, we look at \(c\). If \(c\geq5\), we do \(b + 1\); if \(c<5\), we keep \(b\) as it is. But in 89.91, \(b = 9\), \(c = 1\). So we keep \(b\) as 9. So the number rounded to the nearest tenth is 89.9? Wait, no, wait, 89.91. Wait, 89.91 is 89 + 0.9+0.01. When rounding to the nearest tenth, we consider the hundredths place. Since 1 < 5, we round down, so we keep the tenths place as 9. So 89.91 rounded to the nearest tenth is 89.9? Wait, no, wait, 89.91: let's think of it as 89.9 (tenths place) and the next digit is 1. So we don't round up the 9. So the result is 89.9? Wait, no, wait, maybe I messed up. Wait, 89.91: the tenths digit is 9, hundredths is 1. So according to the rounding rule, since 1 < 5, we leave the tenths digit as it is. So 89.91 rounded to the nearest tenth is 89.9? Wait, but wait, 89.91 is closer to 89.9 or 90.0? Wait, 89.91 - 89.9 = 0.01, and 90.0 - 89.91 = 0.09. So 89.91 is closer to 89.9. So the correct rounding is 89.9? Wait, no, wait, 89.91: the tenths place is 9, hundredths is 1. So the rule is: look at the digit to the right of the tenths place (hundredths place). If it's less than 5, we round down, so we keep the tenths digit. So 89.91 rounded to the nearest tenth is 89.9.

Wait, but wait, another way: 89.91. Let's write it as 89.9 + 0.01. The nearest tenth is the nearest multiple of 0.1. The multiples of 0.1 around 89.91 are 89.9 (which is 89.90) and 90.0 (which is 90.00). The distance from 89.91 to 89.90 is 0.01, and to 90.00 is 0.09. So it's closer to 89.90, so we round to 89.9.

Answer:

89.9