







Random assignments 
20190302 

From Ninoshka: Liu and Michi plan to sign up for a drawing class next term.
Drawing is offered during the first 4 periods of the day, and students are assigned randomly to class.
What is the probability that Liu and Michi will have drawing together? Answered by Penny Nom. 





Significant digits 
20170806 

From Pat: The directions for a problem are: "Solve the problem, expressing your answer
using the correct number of significant figures."
Problem
0.0043 divided by 2.04
Answer before using the correct number of significant figures is
0.002107843
Is the correct number of significant figures the number below?
2107843
Pat Answered by Penny Nom. 





The definition of percent ( % ) 
20150307 

From Kenneth: Hello:
I saw this definition online from the Free Dictionary (The Free Dictionary.com) regarding the definition of percent (%):
"Noun 1. a percent sign  a sign (`%') used to indicate that the number preceding it should be understood as a proportion multiplied by 100."
What is this "proportion" multiplied by 100?
When I think of a proportion, I think of a/b = c/d. How can a number preceding the percent sign be understood as a proportion X 100?
I thank you for your reply! Answered by Chris Fisher and Claude Tardif. 





When would one flip the inequality sign? 
20140109 

From Natasha: Would one flip the inequality symbol in this equation: (explain why)
(9a)/(9) > 81
And please explain in what circumstances one would flip the inequality sign
THANKS! Answered by Penny Nom. 





Changing the sign of an inequality 
20120919 

From Bryauna: Why do you change the signs in inequalities?! Answered by Penny Nom. 





I have a sign size regulation I have to meet. 
20101026 

From Scott: I have a sign size regulation I have to meet. The size is .6 meters squared. at first look this would be 2 ft x 2 ft.
I believe it would be larger then that. Can you confirm what the size would be in inches please. Answered by Penny Nom. 





How many zeros? 
20100318 

From jeff: 1 light yr is 6,500 billion miles, the galaxy "Andromeda" is 2,500,000 million light yrs, how many zeros are in this equation ? Answered by Robert Dawson. 





5^2= 25 
20090506 

From tracy: show how to perform this calculation and why
5^2= 25 Answered by Robert Dawson. 





Conversion factor 
20090323 

From kab: Would like to photocopy a Landscape Design. What is the Conversion Ratio or magnification required to convert 1" = 10 feet to 1/4" = 1 foot? Answered by Harley Weston. 





Alpha level 
20080723 

From anonymous: What is the advantage of using an alpha level of .01 versus a level of .05, What is the disadvantage of using a smaller alpha level? Answered by Janice Cotcher. 





The sign of the quotient of two integers 
20080201 

From michelle: without actually dividing, how can you decide whether the quotient of two integers is A. positive B. negative C. 0? Answered by Penny Nom. 





A statistical difference 
20070703 

From a student: I am writing a paper for a grad class in which I am comparing achievement levels of boys and girls. I have data that shows the average marks for girls and boys in each grade 12 subject for the entire province.
My prof want me to show there is a statistical difference. What do I have to do to show this? I don't have access to the raw data, so don't know the SD. Is there anything I can do mathematically with the data that I have? (I can determine n for each set of data, it ranges between 2400 and about 13000 for each subject area.) Answered by Chris Fisher and Harley Weston. 





An octagonal sign 
20070513 

From Cathy: An octagonal sign is made by cutting four identical triangles made from a rectangle calculate area of one of the discarded triangles. length of square=26cmx22cm. length of octagonal sides are 10cm x 13cm Answered by Penny Nom. 





Is 2^2 = 4 or 4? 
20070123 

From Joan: Is 2 squared, when written without parentheses around the 2, 4 or could this correctly be solved by squaring 2 (2 x 2) for an answer of 4? Or, to correctly get an answer of 4, would the problem have to read (2) squared? Answered by Stephen La Rocque. 





Octagonal Stop Sign 
20061023 

From Phil: My colleagues and I are in a discussion about how many true "sides" an octagonal stop sign has. I say that it has 10 true sides because of the front back sides of a stop sign (3D octagon). Is this correct terminology or should the front and back "sides" be referred to as faces  equaling 2? Answered by Paul Betts, Steve La Rocque and Harley Weston. 





Frieze patterns 
20040519 

From Christina: How can I prove that there are only seven unique geometric frieze patterns? Answered by Penny Nom. 





7,473,000,000 divided by 52000 
20030906 

From A student: I am having trouble with a question. 7,473,000,000 divided by 52000. Our calculater gets 147311.5385. I come up with 143711.53846, and then the number starts to repeat itself Answered by Penny Nom. 





Making a blanket 
20030813 

From Liz: Please help me figure this out. I am making a blanket the directions call for a piece of material measuring 72"X45". Instead of one piece I'd like to make a patchwork quilt but the squares need to equal 72"X45". Centered on the bottom of the longest edge is an 18" square. Answered by Harley Weston. 





Rounding 27.27 
20021103 

From A parent: If you have a problem 27.27 and you need to round to the first 7 the answer would be 27 Would 27.0 be acceptable as well or is it completely wrong. Answered by Penny Nom. 





On which assignment did I do better 
20020517 

From Denise: I have 2 writing assignments in class. The first assignment, which had a mean of 10 and a standard deviation of 2, I got a score of 12. The second assignment had a mean of 18 and an s.d. of 3, I got a 21. I need to know which assignment did I do better, relative to my classmates? Answered by Andrei Volodin. 





Frieze Patterns 
19980819 

From Brian Bairstow: I am doing a research project on frieze patterns (also called band patterns or border patterns). I know that there are exactly seven different types of frieze patterns, but I have been unable to find a proof for this. If you could tell me this proof, or tell me some internet sites on which I can find material on this, I would be very grateful. Answered by Chris Fisher. 





Cos(x) Cos(2x) Cos(4x)=1/8 
19970924 

From Tan Wang: How many distinct acute angles x are there for which cosx cos2x cos4x=1/8? Answered by Chris Fisher Harley Weston and Haragauri Gupta. 





Je voulais savoir d'où provient le signe # ?! 
20080117 

From Dimitri: Je voulais savoir d'où provient le signe # ?!
On l'appelle diez, sur les téléphones surtout, mais j'aimerai savoir plus précisément à quoi sert ce signe (autre que sur nos appareils) !
Et pourquoi, en anglais, s'il est placé avant un chiffre, on dit 'number' (par exemple #1, 'Number one').
Son origine m'interesse tout autant que son utilité ! Answered by Claude Tardif. 

