What is the sum of 0.7854 and 0.3927?

What is the sum of 0.7854 and 0.3927?

• A. 0.3927
• B. 0.7854
• C. 1.5708
• D. 1.1781

Answer: (D)

Align the decimals and add from the rightmost digit, carrying to the left as needed. Here both numbers have four digits after the decimal, so you add 0.7854 + 0.3927 step by step: the far right digits give a carry into the next place, and continuing leftward you end up with 1.1781. The carry to the units place means the integer part becomes 1 and the decimal part is 0.1781. This is the correct sum. The other options correspond to just one of the addends or to doubling one addend, not to their total.

Align the decimals and add from the rightmost digit, carrying to the left as needed. Here both numbers have four digits after the decimal, so you add 0.7854 + 0.3927 step by step: the far right digits give a carry into the next place, and continuing leftward you end up with 1.1781. The carry to the units place means the integer part becomes 1 and the decimal part is 0.1781. This is the correct sum. The other options correspond to just one of the addends or to doubling one addend, not to their total.