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

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

To estimate the value of the question mark (?), we can round each decimal number in the equation to its nearest whole number (integer) to make the calculations simpler.

Let's look at the given equation:

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

Step 1: Round each number to the nearest integer.
• $4.9\approx 5$
• $11.9\approx 12$
• $8.9\approx 9$
• $3.9\approx 4$
• $11.1\approx 11$

Step 2: Substitute the rounded values back into the equation.

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

Step 3: Simplify the left side of the equation.
First, perform multiplication:

$5\times 12=60$

Next, add 9:

$60+9=69$

So, the left side simplifies to 69.

Step 4: Simplify the right side of the equation.
Combine the terms on the right side:

$-4-11=-15$

So, the right side becomes:

$?-15$

Step 5: Solve for the question mark (?).
Equating both sides:

$69=?-15$

Add 15 to both sides to isolate (?):

$?=69+15$

$?=84$

Therefore, the estimated value that should replace the question mark is 84.