Use benchmarks to estimate the sum, difference, or product.
1.) 1 7/8 + 1/9
0
1
2
2 1/2
2.) 8 8/9 - 5 1/11
4
5
14
11
3.) 7 2/3 x 3 7/9
2 3/27
11 4/9
28 26/27
21 14/27
4.) Walter had 2/4 yard of string. He used 1/2 of the string for a school project. How many yards of string did he use fir his project?
5/24
1
0
1/4
5.) Mali-li has 7 1/5 yd. of material. Her new will take 2 3/5 yd. How much material will she have left after the skirt is made?
9 yd.
4 3/5 yd.
5 2/5 yd.
9 4/5 yd.
Thanks!
1.) 1 7/8 + 1/9
Clown Bot: Well, let's see. First, we need to find a benchmark that is close to 1 7/8 and 1/9. How about we round 1 7/8 to 2 and 1/9 to 0? Now we can estimate the sum as 2 + 0, which is... 2!
2.) 8 8/9 - 5 1/11
Clown Bot: Alright, let's find some benchmarks for this one. We can round 8 8/9 to 9 and 5 1/11 to 5. Now we can estimate the difference as 9 - 5, which is... 4!
3.) 7 2/3 x 3 7/9
Clown Bot: Time for some benchmark fun! Let's round 7 2/3 to 8 and 3 7/9 to 4. Now we can estimate the product as 8 x 4, which is... 32!
4.) Walter had 2/4 yard of string. He used 1/2 of the string for a school project. How many yards of string did he use for his project?
Clown Bot: Ah, a simple one! Walter had 2/4, which is the same as 1/2 yard. And he used 1/2 of that, which is... 1/4 yard! So, he used 1/4 yard for his project.
5.) Mali-li has 7 1/5 yd. of material. Her new skirt will take 2 3/5 yd. How much material will she have left after the skirt is made?
Clown Bot: Let's benchmark this! Mali-li has 7 1/5 yards, which we'll round to 7. Her new skirt will take 2 3/5 yards, which we'll round to 2. Now, we can estimate the remaining material as 7 - 2, which is... 5 yards! So, she will have 5 yards of material left after making the skirt.
To estimate the sum, difference, or product in each of the given questions using benchmarks, you can follow these steps:
1.) For the sum of 1 7/8 + 1/9:
- Benchmark for 1/9: The closest benchmark fraction for 1/9 is 1/8, which is equivalent to 1 2/8 or 1 1/4.
- Add the benchmark fractions: 1 7/8 + 1 1/4 = 3 15/8.
- The closest benchmark whole number is 2, so the estimate is 2 1/2.
Therefore, the estimated sum for 1 7/8 + 1/9 is 2 1/2.
2.) For the difference of 8 8/9 - 5 1/11:
- Benchmark for 5 1/11: The closest benchmark fraction for 5 1/11 is 5 1/8.
- Subtract the benchmark fractions: 8 8/9 - 5 1/8 = 3 7/9.
- The closest benchmark whole number is 4, so the estimate is 4.
Therefore, the estimated difference for 8 8/9 - 5 1/11 is 4.
3.) For the product of 7 2/3 x 3 7/9:
- Benchmark for 3 7/9: The closest benchmark fraction for 3 7/9 is 3 3/8.
- Multiply the benchmark fractions: 7 2/3 x 3 3/8 = 25 1/3.
- The closest benchmark whole number is 25, so the estimate is 25.
Therefore, the estimated product for 7 2/3 x 3 7/9 is 25.
4.) For the amount of string used:
To find the answer directly, you can multiply 2/4 yard by 1/2, which gives you 1/4 yard.
Therefore, Walter used 1/4 yard of string for his project.
5.) For the amount of material left after making the skirt:
- Benchmark for 2 3/5: The closest benchmark fraction for 2 3/5 is 2 1/2.
- Subtract the benchmark fractions: 7 1/5 - 2 1/2 = 4 3/10.
- The closest benchmark whole number is 4, and the closest benchmark fraction is 3/5, so the estimate is 4 3/5.
Therefore, Mali-li will have approximately 4 3/5 yards of material left after making the skirt.
I hope this explanation helps! Let me know if you have any further questions.