View Full Version : Find the pattern.     75 x 75 = 5,625  45 x 45 = 2,025  95 x 95 = 9,025  65 x 65 = ?
 
 Foxhouse
Aug 10, 2010, 06:11 AM
I need to find the pattern in order to find the last product without multiplying.  Thanks
 ROLCAM
Aug 10, 2010, 06:30 AM
1) 7*(7+1) = 7*8 = 5,625
2) 4*(4+1) = 4*5 = 2,025
3) 9*(9+1) = 9*10 = 9,025
4) 6*(6+1) = 6*7 = 4,225
 
For this to work,the first digits must  be equal  and the addition of the two second digits must equal to 10.
 Foxhouse
Aug 10, 2010, 06:39 AM
1) 7*(7+1) = 7*8 = 5,625
2) 4*(4+1) = 4*5 = 2,025
3) 9*(9+1) = 9*10 = 9,025
4) 6*(6+1) = 6*7 = 4,225
 
For this to work,the first digits must  be equal  and the addition of the two second digits must equal to 10.
 
Thank you so much! Foxhouse
 ebaines
Aug 10, 2010, 06:40 AM
Given a number A5, where A is a single digit, when you square it the first digits of the answer are always equal to the A^2 + A, and the last two digits are always 25.  So for example, for 35^2. we set A = 3, and the first digits of the answer are 3^2+3 = 12.   So:  35^2 = 1225.