Homework Help: math

Posted by lesly on Monday, March 14, 2011 at 5:02pm.

Find a shortcut for computing the sum: 1+3+5+7++11+13+15+17=?? Explain your shortcut and how you could use this same shortcut to find the sum of all the odd numbers form 45 to 99.

math - Reiny, Monday, March 14, 2011 at 5:39pm
what is the sum of the 1st and last?
what is the sum of 2nd and 2nd last ?
what is the sum of 3rd and 3rd last ?

mmmmhhhh?
math - Anonymous, Monday, March 14, 2011 at 6:16pm
1+17=18
3+15=18
5+13=18
7+11=18

4*18=72

45+99=144
47+97=144
49+95=144
51+93=144
53+91=144
55+89=144
57+87=144
59+85=144
61+83=144
63+81=144
65+79=144
67+77=144
69+75=144
71+73=144

14*144=2016

Answer this Question

Related Questions

math - is there a shortcut to solve organized lists if so what is the shortcut?
Math - What is a shortcut for finding the sum of all numbers from 1-99?
Algebra - I want to get the first four terms of the expansion of this expression...
Statistics - Hi, My professor gave us the formulas for sample variance and ...
Algebra - Is there a shortcut to foiling an equation? I always thought that FOIL...
probability - two fair six-sided dice are rolled and the sum of the dots on the ...
calc - Use L’Hopital’s rule to find the limit of this sequence (n^100...
calc2 - Use L’Hopital’s rule to find the limit of this sequence (n^100...
Math: Derivatives - Use the shortcut rules to mentally calculate the derivative ...
Chemistry - Use the shortcut rules to assign an oxidation state to each atom in...

For Further Reading

First Name:
School Subject:
Answer: