







What does 2xy mean? 
20111207 

From dana: I don't know what is 2xy what does that mean? is it 2x+2y or 2x times y
Please help! thank you for your time!! :) Answered by Penny Nom. 





pi/2 + 12/13 
20110524 

From Jen: If you have (pi/2) and you want to add it to (12/13), how would you go about it? Answered by Chris Fisher. 





express the number 100 using the same figure 6x 
20060617 

From A student: express the number 100 using the same figure 6x Answered by Stephen La Rocque. 





Right angles 
20060125 

From AshLee: I was recently given a challenge in my Algebra class. My teacher wanted to know about a right angle. He said he would give five bonus points to the person that could bring in information. (I know five bonus points may not seem like a lot but in this class, they are.) I looked on this site and I found out why it was called a right triangle, but my teacher want to know where did that theory come from. I was wondering too... not just because of the bonus points. Answered by Penny Nom. 





Why is the letter J used for the integers? 
20040113 

From Amanda: Why is the letter J used to represent intergers as a symbol? Answered by Penny Nom. 





< and > 
20020830 

From Kelsey: What is the origin of the greater (>) than and less (<) than signs? Answered by Harley Weston. 





Why do integers have the symbol of Z? 
20020111 

From Stephanie: Why do integers have the symbol of Z? Natural numbers have the symbol of N, whole numbers have the symbol of W. Our professor has asked us to find out why the letter Z is represented for integers. Answered by Penny Nom. 





Division symbol 
20011212 

From Amanda: What is the name of the symbole used in a long divison problem that seperates the two factors? It looks like a little house. Answered by Penny Nom. 





Sigma 
20010331 

From A student: What does the Sigma symbol mean in mathematics? Answered by Penny Nom. 





Infinity Symbol 
19990713 

From Mark E. Kelly: There is a symbol that looks like a sideways 8 that is used to represent infinity. Does it have a name? Answered by Doug Farenick and Penny Nom. 





The origin of angles 
19980224 

From Marc Poulin: I'm currently teaching angles to students in grade 10 and I've been asked what's the origin of the terms degrees, radians and gradians. I know that the radians come from the sexagesimal numerical system of the Babylonians but my kids wanted to know dates and persons who would have brought these terms first. Answered by Harley Weston. 

