Adding and Estimation Worksheet - Free Printable

Problem Overview:

The task involves estimating the sum of each addition equation and then calculating the actual sum to compare the two. This helps in understanding how close the estimate is to the actual value.

Steps to Solve:

1. Estimate the Sum: Round each number to the nearest ten or hundred (depending on the numbers) to make the addition easier.
2. Calculate the Actual Sum: Perform the exact addition without rounding.
3. Compare: Compare the estimated sum with the actual sum to see how accurate the estimate was.

Solution:

#### Problem 1:
- Equation: \( 145 + 325 \)
- Estimate:
- Round \( 145 \) to \( 150 \)
- Round \( 325 \) to \( 330 \)
- Estimated sum: \( 150 + 330 = 480 \)
- Actual:
- Actual sum: \( 145 + 325 = 470 \)

#### Problem 2:
- Equation: \( 572 + 227 \)
- Estimate:
- Round \( 572 \) to \( 570 \)
- Round \( 227 \) to \( 230 \)
- Estimated sum: \( 570 + 230 = 800 \)
- Actual:
- Actual sum: \( 572 + 227 = 799 \)

#### Problem 3:
- Equation: \( 166 + 622 \)
- Estimate:
- Round \( 166 \) to \( 170 \)
- Round \( 622 \) to \( 620 \)
- Estimated sum: \( 170 + 620 = 790 \)
- Actual:
- Actual sum: \( 166 + 622 = 788 \)

#### Problem 4:
- Equation: \( 608 + 321 \)
- Estimate:
- Round \( 608 \) to \( 610 \)
- Round \( 321 \) to \( 320 \)
- Estimated sum: \( 610 + 320 = 930 \)
- Actual:
- Actual sum: \( 608 + 321 = 929 \)

#### Problem 5:
- Equation: \( 455 + 213 \)
- Estimate:
- Round \( 455 \) to \( 460 \)
- Round \( 213 \) to \( 210 \)
- Estimated sum: \( 460 + 210 = 670 \)
- Actual:
- Actual sum: \( 455 + 213 = 668 \)

#### Problem 6:
- Equation: \( 326 + 321 \)
- Estimate:
- Round \( 326 \) to \( 330 \)
- Round \( 321 \) to \( 320 \)
- Estimated sum: \( 330 + 320 = 650 \)
- Actual:
- Actual sum: \( 326 + 321 = 647 \)

#### Problem 7:
- Equation: \( 309 + 381 \)
- Estimate:
- Round \( 309 \) to \( 310 \)
- Round \( 381 \) to \( 380 \)
- Estimated sum: \( 310 + 380 = 690 \)
- Actual:
- Actual sum: \( 309 + 381 = 690 \)

#### Problem 8:
- Equation: \( 486 + 201 \)
- Estimate:
- Round \( 486 \) to \( 490 \)
- Round \( 201 \) to \( 200 \)
- Estimated sum: \( 490 + 200 = 690 \)
- Actual:
- Actual sum: \( 486 + 201 = 687 \)

Final Answers:

\[
\begin{array}{|c|c|c|}
\hline
\text{Problem} & \text{Estimated Sum} & \text{Actual Sum} \\
\hline
1 & 480 & 470 \\
2 & 800 & 799 \\
3 & 790 & 788 \\
4 & 930 & 929 \\
5 & 670 & 668 \\
6 & 650 & 647 \\
7 & 690 & 690 \\
8 & 690 & 687 \\
\hline
\end{array}
\]

Boxed Final Answer:

\[
\boxed{
\begin{array}{|c|c|c|}
\hline
\text{Problem} & \text{Estimated Sum} & \text{Actual Sum} \\
\hline
1 & 480 & 470 \\
2 & 800 & 799 \\
3 & 790 & 788 \\
4 & 930 & 929 \\
5 & 670 & 668 \\
6 & 650 & 647 \\
7 & 690 & 690 \\
8 & 690 & 687 \\
\hline
\end{array}
}
\]