Directions: What approximate value should come in place of the question mark (?) in the following equation?

209.97 + 39.98% of 649.95 + ? = 749.98

The correct option is 280.

Given equation:

$209.97+39.98\%\text{of}649.95+?=749.98$

To determine the approximate value, round off each term to its nearest convenient whole number:

209.97 ≈ 210
39.98% ≈ 40%
649.95 ≈ 650
749.98 ≈ 750

Substitute these approximate values into the equation:

$210+40\%\text{of}650+?=750$

Calculate 40% of 650:

$40\%\text{of}650=\frac{40}{100}\times 650=4\times 65=260$

Substitute this value back into the equation:

$210+260+?=750$

Add the numbers on the left side:

$470+?=750$

Subtract 470 from 750 to solve for ?:

$?=750-470$

$?=280$

Thus, the approximate value that should come in place of the question mark is 280.