fun math puzzles (1)
TRANSCRIPT
FUN MATH PUZZLES
As a math major, anything that becomes challenging is fun for me. You may feel the same way is math is your thing
I cannot guarantee all the puzzles will be fun, but I can guarantee that some of the puzzles will be very challenging.
Eventhough the skills that you need is basic math, some of these puzzles will require some reflection before you figure them out.
Try to do the puzzles yourself before looking at the solution at the end of the page
The puzzles on this page are warm ups. More complicated puzzles will be added on a regular basis
Let's get started with some fun math puzzles!
Puzzle #1:Use four 5s and some of the symbols +, ×, −, and ÷ to give expressions for 0, 1, 2, and 5
Puzzle #2:Use the two isosceles triangles below to make a star?
Puzzle #3:It takes 1629 digits to number the pages of a book. How many pages does the book have?
Puzzle #4:Use only 4 straight lines to cut a pizza into 11 pieces?
Puzzle #5:would you rather work for 30 days and get paid 5 millions dollars, or be paid 1 cent the first day, 2 cents the second day, 4 cents the third day, and so on...?
Puzzle #1 solution:
5 − 5 + 5 − 5 = 0
5 − 5 + 5 ÷5 = 1
5 ÷5 + 5 ÷5 = 1 + 1 = 2
5 × (5 − 5) + 5 = 5
Puzzle #2 solution:
Puzzle #3:
From page #1 to page # 9, there are 9 pages
From page #10 to page # 99, there are 90 pages. However, since each page number has 2 digits, there are 180 digits from page # 10 to page # 99
From page #100 to page # 999, there are 900 pages. However, since each page number has 3 digits, there are 2700 digits from page # 100 to page # 999
Since there are 1629 digits, we know so far that number of pages is less than 900
Now, we need to find out how many digits there are for those pages greater than 99 or those pages with 3 digits
Since there are 189 digits for pages with less than 3 digits, we can subtract 189 from 1629 digits to find the number of pages with 3 digits
1629 − 189 = 1440
1440 represents the pages with 3 digits, so number of pages with 3 digits = 1440/3 = 480
Thus, total number of pages = 480 + 90 + 9 = 579 pages
Puzzle #4 solution:
Puzzle #5:
The trick is to find out how much money you make in 30 days if you get 1 cent the first day, 2 cents the second day, 4 cents the third day, and so on... Day 1: 1 cents
Day 2: 2 cents
Day 3: 4 cents
Day 4: 8 cents
Day 5: 16 cents
Day 6: 32 cents
Day 7: 64 cents
Day 8: 128 cents
Day 9: 256 cents
-------
-------
-------
-------
Keep mutliplying by 2
-------
-------
-------
-------
Day 30: 536,870,912 cents
536,870,912 cents/100 = 5,368,709.12 dollars and 5,368,709.12 is bigger than 5,000,000
Therefore, you are better off taking 1 cent the first day, 2 cents the second day, 4 cents the third day, and so on... until the 30th day