Evaluate (145.17 − 76.3006) − 48.164.

Step-by-step solution

1. 1

   Work the bracket first, and pad to a common number of decimal places. The three numbers carry $2$, $4$ and $3$ decimal places. Writing trailing zeros so that all have $4$ makes the columns line up and prevents digits from being subtracted out of place — the single most common source of error here:

   $145.1700-76.3006$

2. 2

   Do the first subtraction. Borrowing where needed,

   $145.1700-76.3006=68.8694$

   Quick estimate: $145-76=69$, so an answer just under $69$ is right.

3. 3

   Pad the second subtrahend and subtract.

   $68.8694-48.1640$

4. 4

   Complete the calculation.

   $68.8694-48.1640=20.7054$

   $\boxed{20.7054}$

5. 5

   Check by adding back. $20.7054+48.164=68.8694$, and $68.8694+76.3006=145.1700$ ✓. Rebuilding the original value from the answer catches both borrowing mistakes and misplaced decimal points at once.