High School

Giacomo rounded 38.627 to 38.6. Samantha rounded the same number to 38.62.

Who is correct? Explain your reasoning.

Answer :

To solve the problem of determining who rounded the number 38.627 correctly, let's break it down step-by-step:

1. Understanding rounding to one decimal place (Giacomo's method):
- Giacomo rounded 38.627 to one decimal place.
- To do this, we need to look at the second decimal place (the "2" in 38.62).
- If this number is 5 or greater, we round the first decimal up. In this case, since 2 is less than 5, the number remains the same for the first decimal place.
- Therefore, rounding 38.627 to one decimal place correctly gives us 38.6.
- So, Giacomo's rounding is correct.

2. Understanding rounding to two decimal places (Samantha's method):
- Samantha rounded 38.627 to two decimal places.
- To do this, we examine the third decimal place (the "7" in 38.627).
- If this number is 5 or greater, we round the second decimal place up. Here, since 7 is greater than 5, we must round up the second decimal place by 1.
- Therefore, the correct rounding of 38.627 to two decimal places is 38.63.
- So, Samantha's rounding of the number to 38.62 is not correct.

In conclusion, Giacomo is correct in rounding the number 38.627 to 38.6 when considering one decimal place. Samantha’s rounding does not align with the proper method for two decimal places.