Writing in Math - How can estimating help you add two-digit numbers?
Benchmark numbers are easier to add-usually ending in 0's or 5's.
Ex:
28+31 can be turned into 30+30. 28 was rounded up to 30, and 31 was rounded down to 30.
4 and lower is rounded down; 5 and higher is rounded up. If the number is 3,4,5,6 or 7 it is rounded to five, if you're getting more specific.
I hope this helps; but I'm only in 6th grade so I'm not sure (:
how can estimating help you add two digit numbers
Estimating can be a helpful strategy when adding two-digit numbers because it allows you to quickly get an approximate answer. Estimating involves rounding the numbers to their nearest tens or to a more manageable value and then performing the addition.
Here's how you can use estimating to add two-digit numbers:
Step 1: Round each two-digit number to the nearest ten. For example, if you have 47 and 83, you would round them to 50 and 80, respectively.
Step 2: Add the rounded numbers together. In this case, 50 + 80 = 130.
Step 3: The estimated sum is 130. This is a quick approximation of the actual sum.
Now, to find the exact sum, you can perform the addition using the actual two-digit numbers.
In this example, you would add 47 and 83 by placing the numbers vertically, aligning the ones place:
```
47
+ 83
------
```
Start by adding the ones place: 7 + 3 = 10. Write down the 0 and carry over the 1 to the tens place.
```
47
+ 83
------
0
```
Next, add the tens place: 4 + 8 + 1 (carried over) = 13. Write down the 3 and carry over the 1 to the hundreds place.
```
47
+ 83
------
30
```
Finally, add the hundreds place: 1 (carried over) = 1. The sum of 47 and 83 is 130, which matches the estimated sum.
Estimating helps you quickly determine if your final answer is reasonable. It can be especially useful when working with larger numbers or when you don't have access to a calculator.