William adds two values, following the rules for using significant figures in computations. He should write the sum of these two numbers by using

the same number of decimal places as the least precise value.

the same number of decimal places as the most precise value.

a range of the number of significant figures in the two values.

an average of the number of significant figures in the two values.

when it comes to adding or subtracting numbers, his final answer should have the same number of decimal places as the least precise value.

For example if you add 2 numbers; 10.443 + 3.5, 10.443 has 3 decimal places and 3.5 has only one decimal place.

Therefore 3.5 is the less precise value.

So when adding these 2 values the final answer should have only one decimal place.

after adding we get 13.943 but it can have upto one decimal place. then the second decimal place is less than 5 so the answer should be rounded off to 13.9.

the answer is the same number of decimal places as the least precise value