Can somebody help me with my sisters 4th grade homework?

Question

Heres the question: Let's say your grandpa really likes you and decides to give you one penny one day, two pennies the next day, four pennies the third day, eight pennies the day after that. Each day he gives you twice as many pennies as the day before. If he keeps this up for a month, how much money will you have gotten from him by then? If you can't answer, can you approximate how much money. Ok thats the end of the question. Keep in mind that this is 4th grade math so there must be a simple way to do this. Also since this is 4th grade math the answer can't be in the billions. If you can solve it with please make sure you show your work thanks.

Answer 1

It's an exponent question. Any number to the exponent 0 is defined as 1 and any number to the exponent 1 is that number itself. So:
1st day, 2^0 = 1 +
2nd day, 2^1 = 2 + ...
30th day, 2^29
I didn't start using sigma notation in algebra until senior high school or even university, however, if your sister is studying the concept, then the expression would be:
sigma 2^(n-1) where n=1...30

This seems like awfully complicated math for a Gr.4.

Answer 2

Depending on the number of days in the month, there would be exactly $10,737,418.23 after 30 days or $21,474,836.47 after 31 days. Solution: the sum after day 1 is 2^1-1=1; sum after day 2 is 2^2-1=3; then 2^3-1=7 and so on; so after day 30 it is 2^30-1. I'm guessing this is too advanced for a 4th grader, so I suppose answering "a very large number" might suffice.

Answer 3

I am a fourth grade math teacher & this question is stupid. I am pretty sure that her teacher wants her to use a problem-solving strategy such as Make a Chart or Draw a Picture. However, she was not clear in her question as to how long the month is, nor whether she wants the students to express their answer in pennies, dollars, etc. She will get a million different answers on Monday....

Answer 4

Would it be acceptible to draw up a chart, like a calander. put your earnings in each grid square accordingly. 1 on the 1st, 2 onthe 2nd, 4 on the 3rd etc (doubling every day) untill youve filled it, then add it all up. I could do it but couldnt show you the work besides by the time you get this, you'll probably already have your answer.

Answer 5

Is it February, June or August? 28, 29, 30, 31 or 31 days?

Answer 6

I'M 70 and have no patience for this. i could do it, but why not let her do it herself. all she needs is a calendar and a calclator. in the calendar squares, write the doubled amt from prev day, then add all the squares with the calculator. add several times in case of error.

Answer 7

if there is 32 days the answer is 64 im pretty sure just take how ever many of days there are and times it by 2

Answer 8

meeghanmk, your English is as incorrect as your math. She would have more than 62 in six days.

Answer 9

$5,368,709.12