Question

Estimate the following sum using front-end estimation: 48.1 + 29.7 + 11.8. Options: Option 1: 100 Option 2: 70 Option 3: 90 Option 4: 80

Answer 1

Using front-end estimation, 48.1, 29.7, and 11.8 are rounded to 50, 30, and 10 respectively. The estimated sum of these numbers is 90. Hence, the correct option is Option 3.

Step-by-step explanation:

The student has asked to estimate the following sum using front-end estimation: 48.1 + 29.7 + 11.8. To use front-end estimation, we focus on the leading digits (the 'front end') of the numbers involved. Therefore, we estimate 48 as about 50, 29 as about 30, and 12 as about 10 (since we generally round to the nearest ten).

Adding these estimated values together, we get:

• 
  
• 50 (rounded from 48.1)
• 
  
• 30 (rounded from 29.7)
• 
  
• 10 (rounded from 11.8)

The estimated sum is 50 + 30 + 10 = 90.

Therefore, the option closest to our front-end estimation is Option 3, which is 90.

Answer 2

The sum of 48.1, 29.7, and 11.8 is best estimated as 90 using front-end estimation, which is Option 3.

Step-by-step explanation:

To estimate the sum using front-end estimation, you look at the leftmost digits (the 'front end') of each number and add those, ignoring the smaller place values. Here are the numbers rounded to the nearest ten:

48.1 is approximately 50

29.7 is approximately 30

11.8 is approximately 10

Adding these estimates together:

50 + 30 + 10 = 90.

Therefore, the best estimate for the sum of 48.1 + 29.7 + 11.8 using front-end estimation is 90, which corresponds to Option 3.