Estimate each of the following using the general rule:

a. 730 + 998

b. 796 – 314

c. 12904 + 2888

d. 28292 – 21496

To estimate the sums and differences in your examples, we can use a simple rounding technique. This method allows us to quickly find approximate values without doing the exact calculations. Let’s break down each problem step by step.

Estimating Sums and Differences

Example A: 730 + 998

First, we round each number to the nearest hundred. For 730, it stays as 700, and for 998, we round it up to 1000. Now, we can add these rounded numbers:

• 700 + 1000 = 1700

So, the estimated sum of 730 + 998 is approximately 1700.

Example B: 796 – 314

Next, we round these numbers to the nearest hundred as well. Rounding 796 gives us 800, and rounding 314 brings us down to 300. Now we can perform the subtraction:

• 800 - 300 = 500

The estimated difference for 796 – 314 is about 500.

Example C: 12904 + 2888

For this addition, we round 12904 to 13000 and 2888 to 3000. Adding these rounded figures gives us:

• 13000 + 3000 = 16000

Thus, the estimated sum of 12904 + 2888 is around 16000.

Example D: 28292 – 21496

In this case, we round 28292 to 28000 and 21496 to 21000. Now, we can subtract:

• 28000 - 21000 = 7000

The estimated difference for 28292 – 21496 is approximately 7000.

Summary of Estimates

To summarize, here are the estimated results:

• 730 + 998 ≈ 1700
• 796 – 314 ≈ 500
• 12904 + 2888 ≈ 16000
• 28292 – 21496 ≈ 7000

This estimation technique is particularly useful for quickly assessing calculations in everyday situations, allowing you to make informed decisions without needing precise numbers. It’s a handy skill to develop!