Estimate the value that should replace the question mark (?) in the following equation (an exact calculation is not required).

$4.9\times 11.9+8.9=?-3.9-11.1$

Correct Answer: The correct option is 84.

Step-by-Step Explanation:

We are given the following equation to estimate:

$4.9\times 11.9+8.9=?-3.9-11.1$

Since an exact calculation is not required, we can round each decimal number to its nearest whole number (integer) to make the calculation simpler:

• 4.9 is approximately equal to 5

• 11.9 is approximately equal to 12

• 8.9 is approximately equal to 9

• 3.9 is approximately equal to 4

• 11.1 is approximately equal to 11

Now, substitute these approximate values into the equation:

$5\times 12+9\approx ?-4-11$

Next, simplify both sides of the equation step-by-step:

Calculate the left side using BODMAS rules (Multiplication before Addition):

$5\times 12=60$

$60+9=69$

Simplify the right side:

$?-4-11=?-15$

Now, equate both simplified sides:

$69=?-15$

Solve for the missing value (?):

$?=69+15$

$?=84$

Thus, the estimated value that should replace the question mark (?) is 84.