estimate 0.73*4 [is it 28 or 2.8 or 4?
estimate 6.92 divided by 7 [is it 9 or 9.00 or 0.09 or 0.9?
find the value of 5 *[3+4.2] +7?
find the value of 12-3r if r=2.1?
solve; 0.5s=21
2006-07-11 09:42:33 · 6 answers · asked by Anonymous in Education & Reference ➔ Homework Help
1) estimate 0.73 x 4.
think about it like this, 0.7 x 4, which is 2.8 (just like 7 x 4 but move the decimal one place)
2.) estimate 6.92 divided by 7.
think about it like 7 divided by 7, which is 1.
3.) 5 x [3 + 4.2] + 7
Order of operations: Please excuse my dear aunt sally. Parentheses first, so 3 + 4.2, which is 7.2. Then multiply 5 times 7.2 and you get 36. Then add 7, and you get 43.
4.) 12 - 3r ; r = 2.1
Again, order of operations. First multiply 3 and 2.1 and you get 6.3. Then subtract from 12 (12 - 6.3) and you get 5.7.
5.) 0.5s = 21
In order to figure out what s is, you have to think. If 5 times s is 21, then 21 divided by s is 5, or 21 divided by 5 is s. It's essentiall reverse order of the order of operations. So divide both sides of the equal sign by 0.5, and you get s = 42.
2006-07-11 09:50:11 · answer #1 · answered by Anonymous · 2⤊ 0⤋
Regarding the estimates, you are looking at the order of magnitude of the numbers ininvolved. In the first example, 0.73 best rounds to 1, so the answer is going to be closest to 1 times 4, which would be 2.8.
In the second, 6.92 is about 7, so the estimate is going to be closest to 7 divided by 7, which is 1. Thus, the estimated answer is 0.9.
For the others:
5*[3+4.2] + 7 = 5*(7.2) + 7 = 36 + 7 = 43
12 - 3r = 12 - 3(2.1) = 12 - 6.3 = 5.7
0.5s = 21 => s = 21/(0.5) = 42
Hope that helps.
2006-07-11 18:18:42 · answer #2 · answered by Ѕємι~Мαđ ŠçїєŋŧιѕТ 6 · 1⤊ 0⤋
With estimates, you can say to yourself "what's 7 x 4? 28. Well, .73 is close to one-tenth of 7, so . . . ." (2.8 is what you're looking for).
With the second two problems, do the stuff in parenthesis first, or in the r case, the 3 * 2.1.
And in the last problem, all you need to do is 21 / .5 (also known as 21 x 2)
2006-07-11 16:47:50 · answer #3 · answered by jshclhn 2 · 1⤊ 0⤋
Use the calculator the computer has a calculator
For the last three i will help you
PIMDAS= do the parentheses then multiply then add or subtract.
Last one= 21 divided by .5
2006-07-11 16:48:48 · answer #4 · answered by greenwhitecollege 4 · 1⤊ 0⤋
Doesn't your computer have a calculator type program installed? if so, then ALL of your answers will be solved if you use your calculator right. Hope this helps.
2006-07-11 16:46:11 · answer #5 · answered by I like horses 1 · 1⤊ 0⤋
You really ought to listen to your teacher. Those aren't that heard if you think about it! I'm in seventh grade and I can do harder stuff than that!!
2006-07-11 16:46:59 · answer #6 · answered by pianoman.jeremy 4 · 1⤊ 0⤋