Friday, August 24, 2007

Number & Operation 27

Miss Thompson wanted to plan how to contact her students by phone in case the field trip they were going on the nextg day needed to be cancelled. She decided to call one student, who would then call 2 other students. Each of these students would then call 2 other students. This telephone chain would continue until all the students had been called. Miss Thompson has 31 students. How many students will need to make phone calls if Miss Thompson calls the first student?



How do you know? Explain using words.

56 comments:

Anonymous said...

21 students would have to call.

Anonymous said...

15 because you would have to round then you take 30 divided by 2 and you get 15

Anonymous said...

15 students would need to make phone calls because that is about have of 31.

Anonymous said...

15 because 30 divided by 2 is 15 and there is 1 left over but that 1 that is left over is what Miss Thompson called.

Anonymous said...

15 because because the rest would not have to call anyone because every one was already called

Anonymous said...

16 students would have to call because if you use a factor tree starting with 1 student then break it down in to the 2 students the stuudent called and ect. and finish with 31 students you count the number of student that called 2 others and end with 16 students that called.

Anonymous said...

15, because if miss tompson calls the first one there is 30 students left, and 30 divided be 2 = 15.

Anonymous said...

15 students woiuld have to call because u already called 1 so 31-1=30 then each student would have to two times which means 30/2= 15students

Anonymous said...

15 will have to call 2 people,she called the first 1.

Anonymous said...

15 students would have to call because she called the first student and that student is sopposed to call 2 others. It would keep on going until all of the students have been told about the feild trip.

Anonymous said...

15 because If she calls the first 1 there are 30 left to call and if every1 calls 2 people then ebery1 would know

Anonymous said...

15,because 30 divided bye 15=2 so there would be 1 student left.

Anonymous said...

if you round to 30 then u divide it by 2 then u get 15 students

Anonymous said...

15,because 30 divided by 15 is 2 so 1 student left.

Anonymous said...

11 kids would have to call.Because the kids have to call 2 people and those people would call 2 people and so on.

Anonymous said...

if you take 30 and divide it by 2 you get 15 so 15 students would have to make phone calls because miss thompson had already made the first 2

Anonymous said...

15 because if you divide 30 by 2 it is 15. there sould be 1 left over and that is the one mr. thompson cslled.

Anonymous said...

15 students would call, but the one that Miss thompson called is the 31st the others are called but students

Anonymous said...

15 would have to call because 15x2 is 30 and the one is the original one that miss. t called
*)wHiTnEy(*

Anonymous said...

15 where taken


how did i get it i take 30 divide by 2

Anonymous said...

15 because 30 divided by 2 is 15 and there will be 1 left over and that is the one that she called

Anonymous said...

the first sudnet has to make at lest 30 calls

Anonymous said...

15 Students would have to call someone because if you take 31 divided by two you get 15, or about. So 15 students will have to call someone.

Anonymous said...

15 students that is about half of 31

Austen Iverson-South Dakota said...

18 because you make a tree and I didnt cout the ones at the top of the tree because they didnt have to call anyone. so the answer is 18

Anonymous said...

forvgot the R in my nam

Anonymous said...

15 would call because if she called 31 student about half of 31 is 15

Anonymous said...

i would have to say 15 becuase if you take 30 divied bye 2 then you get 15.ps fell better.

Anonymous said...

15 because 30 divided by 2 = 15 and then you add the one the teacher called and that would make 16 students.

Anonymous said...

Miss Thompson would call 1 (student), who would then call 2 and 3. 2 would call 4 and 5, 3 would call 6 and 7. 4 would call 8 and 9, ect. 15 students would have call, because each student needed to call 2 other students.

Anonymous said...

15 because they all call two and she has already called 1

Anonymous said...

15, because if Ms. Thompson calls the first one there is 30 students left, and 30 divided by 2 = 15.

Anonymous said...

15 students will have to call other students

Anonymous said...

15 students would be called because 2 divide by 30 is 15

Anonymous said...

15 because its half of 30

Anonymous said...

21 STUDENTS WOULD HAVE TO CALL

Anonymous said...

15 students will have to call 2 people and 1 person will only have to call 1 person

Anonymous said...

15 calls will be made

Anonymous said...

16 because 15/2=15 then add the 1 the teacher called

Anonymous said...

15 will have to call. I just drew a picture

Anonymous said...

15 students, because you would take 30 divided by 2 and you get 15.

Anonymous said...

15 students would have to make phone calls because 15+15=30 and thhat is only one less then 31.

Anonymous said...

15 student becasue the rest dont have to call.

Anonymous said...

15 students would have to call because i made a tree type of thinger and i got 15

Anonymous said...

15 becouse 15 divided by 2 is 30 and Miss Thompson had called the left over student

Anonymous said...

the answer is 14

Anonymous said...

15 students because u called one so 31-1 is 30 she then 30 / 2 is 15.

Anonymous said...

30/2= 15 students

Anonymous said...

15 students needed to call. Because 15x2=30 plus the one Miss.Thompson called which would make it be 31 students.

Well bye now have a awesome weekwnd and Miss. Thompson hope you get better soon

Anonymous said...

15 students because 31 students - 1 = 30 30 divide by 2 = 15

Anonymous said...

15 because 15 is half of 30 and Miss Thompson is 31

Anonymous said...

15 students

Anonymous said...

15 students because you would have to round then you take30 and divid it by 2 and you get 15

Anonymous said...

15 students need to call because 15 t 15 = 30 students add one more and you get 31

Anonymous said...

15 because if each called two students it is like it is divided in half plus the one miss thompson called would equal 31

Anonymous said...

15 students will be needed to call all 31 students