Front-end estimation is

• A. An estimation method focusing on the front digits
• B. An estimation method focusing on the back digits
• C. An estimation method focusing on rounding to nearest ten
• D. An estimation method focusing on the middle digits

Answer: (A)

Front-end estimation uses the most significant digits of the numbers to form a quick, approximate total. You replace each number with the value formed by its leftmost digits (often the hundreds or tens place, depending on the numbers) and ignore the trailing digits, then add those leftmost values. This emphasizes the size of the total by concentrating on the part of each number that carries the greatest place value. For example, 347 plus 682 is roughly 300 plus 600, which gives 900 as a quick estimate (the exact sum is 1,029). For two-digit numbers like 47 and 68, you would use 40 and 60 to get 100 as the estimate. This method is especially helpful for mental math and for checking whether an answer is reasonable. It centers on the leftmost digits because they carry the most weight in the total.