jonesloonybin Posted January 28, 2010 Share Posted January 28, 2010 We are having some problems with our math. The answer we all got does not match what the book shows. Could you all give us a hand? 16-4*8+4to the 2nd power-(-18)-(-9) We keep getting 19 as the answer but the book says 27. Could you please help us??? (* = multiply) Thanks! Quote Link to comment Share on other sites More sharing options...
Pamela H in Texas Posted January 28, 2010 Share Posted January 28, 2010 (edited) I got the same as the book.... 16-4*8+4²-(-18)-(-9) First do the squared so now you have 16-4*8+16-(-18)-(-9) Then multiply so now you have 16-32+16+18+9 (minus a negative just equals adding a positive) Then just add/subtract the 16-32+16 cancels out to zero 18+9 = 27 Would you do me a HUGE favor? Could you show me how y'all got 19? I'm an education major and want to teach middle school math. I thought that figuring out what y'all did would help me, but I can't figure it. I know that usually I'll have the young person's work in front of me in order to see their trouble, but... Edited January 28, 2010 by 2J5M9K Quote Link to comment Share on other sites More sharing options...
EKS Posted January 28, 2010 Share Posted January 28, 2010 I got 27 as well. 16-4*8+4^2-(-18)-(-9) 16-32+16-(-18)-(-9) -16+16-(-18)-(-9) -(-18)-(-9) 18+9 27 Quote Link to comment Share on other sites More sharing options...
babysparkler Posted January 28, 2010 Share Posted January 28, 2010 16-(4*8)+(4to the 2nd power)-(-18)-(-9) 16 -32 + 16 +18 +9 = 27 Quote Link to comment Share on other sites More sharing options...
Perry Posted January 28, 2010 Share Posted January 28, 2010 We are having some problems with our math. The answer we all got does not match what the book shows. Could you all give us a hand? 16-4*8+4to the 2nd power-(-18)-(-9) We keep getting 19 as the answer but the book says 27. Could you please help us??? (* = multiply) Thanks! I'd rewrite it like this: 16 -(4*8) +(4squared) - (-18) -(-9)= 16 - 32 + 16 + 18 +9= =27 Order of operations is important. You have to square the 4 first, and multiply, before you can do any adding or subtracting. Quote Link to comment Share on other sites More sharing options...
jonesloonybin Posted January 28, 2010 Author Share Posted January 28, 2010 DOOH! I swear I looked over her work about a hundred times and totally missed that when she did the exponent she put 8 instead of 16. :glare: That of course changed the whole equation. I obviously need more sleep. Thank you all so much for your help. It is just one of those days! lol Thanks Quote Link to comment Share on other sites More sharing options...
********* Posted January 28, 2010 Share Posted January 28, 2010 16-4*8+4to the 2nd power-(-18)-(-9) We keep getting 19 as the answer but the book says 27. Could you please help us??? (* = multiply) Thanks! 16-4*8+4to the 2nd power-(-18)-(-9) 16-32+16+18+9 27 You have to do the multiplication first in an equation, before addition and subtraction. That means in the first step, you multiply the (4x8), and you figure the 4 to the second power. Then you do all the addition and subtraction in the next step. Also, subtracting a negative number is the same as adding; the two negatives equal a positive. Clear as mud, hunh? :tongue_smilie: I didn't read the other replies; maybe someone else explained it better than I did... Quote Link to comment Share on other sites More sharing options...
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