Grades 7-8 Video Solutions 2022-2022_7-8

Video Transcription

Question 7. In the statement below, there are 5 empty spaces. Sanja wants to fill 4 of them with plus signs and 1 with a minus sign so that the statement is correct.  Where should she place the minus sign? We can start off by writing this equation and filling it all out with plus signs. When we do this, we get a total of 81.  Since we know that the equation will end up equaling 45, we can subtract this. When we do this, we get 36.  To figure out which of these plus signs should be turned into a minus sign, we simply have to divide this value by 2 and get our answer. When we do this, we get 18.  So we know that we will have to subtract 18 from all of these pluses, so we can turn that into a minus.  We can check just to make sure, and we find out when we do 6 plus 9 plus 12 plus 15 minus 18 plus 21, we get 45. So the correct answer will be D, between 15 and 18.

Video Summary

Question 7. In the statement below, there are 5 empty spaces. Sanja wants to fill 4 of them with plus signs and 1 with a minus sign so that the statement is correct. Where should she place the minus sign? We can start off by writing this equation and filling it all out with plus signs. When we do this, we get a total of 81. Since we know that the equation will end up equaling 45, we can subtract this. When we do this, we get 36. To figure out which of these plus signs should be turned into a minus sign, we simply have to divide this value by 2 and get our answer. When we do this, we get 18. So we know that we will have to subtract 18 from all of these pluses, so we can turn that into a minus. We can check just to make sure, and we find out when we do 6 plus 9 plus 12 plus 15 minus 18 plus 21, we get 45. So the correct answer will be D, between 15 and 18.

Keywords

math problem

equation

plus sign

minus sign

solution