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Current time:0:00Total duration:5:18

CCSS.Math:

I have six equations here where there is an unknown what I want to do what I want you to do is pause the video right now and try to figure out what that unknown is so in this vid is first one the unknown is a blank what is this blank what is this question mark what is this smiley face what does this letter a need to be in terms of a number what is B what is this star so pause the video now so let's think through each of them this has three times something is equal to 12 so let's think about what we have to multiply by 3 to get to 12 so 3 times 1 is 3 3 times 2 is 6 3 times 3 is 9 3 times 4 is 12 3 times 4 is 12 so we could say that the blank needs to be equal to 4 3 times 4 is 12 now let's work on this one something divided by so question mark divided by 4 is equal to 6 well this is the same thing as saying that question mark is equal to 4 times 6 or you could say 6 times 4 they're the same is equal to 6 times 4 which is the same thing as 4 times 6 so what is 6 times 4 well 6 times 1 is 6 6 times 2 is 12 6 times 3 is 18 6 times 4 is 24 so question mark so this is equal to 24 so question mark must be equal to 24 write that down question mark in this case is equal to 24 now here I have 54 is equal to 9 times smiley face so 9 times what is equal to 54 well let's just skip count with 9 and try to figure that out 9 times 1 is 9 9 times 2 is 18 9 times 3 is 27 notice I'm just adding 9 each time 9 times 4 is 36 9 times 5 is 45 9 times 6 is 54 this is 54 is 9 6 9 times 6 is equal to 54 so we now know that the smiley face so smiley face must be equal to 6 if we replace the smiley face with a 6 of this equation is true 54 is equal to 9 times 6 let's work on this one up here 9 is equal to a divided by 8 well this is the same thing as saying that if a divided by 8 is equal to 9 well that means that 9 times 8 must be equal to a 9 times 8 must be equal to a if I divide a into eight groups and I have 9 in each group that means I have 9 a 9 in a group times 8 groups I must have the total number of things so what is 9 times 8 well 9 times 1 is 9 in fact we already did a lot of our 9 times tables down here we could just keep going 9 times 6 was 54 9 times 7 is 63 9 times 8 is 72 so 9 times 8 9 times 8 is equal to 72 so we can say that a is equal to 72 and if a is equal to 72 then this equation becomes 9 is equal to 72 divided by 8 which is absolutely true 72 divided by 8 is 9 9 times 8 is 72 B is equal to 20 divided by 5 well what's 20 divided by 5 well there's a couple of ways you could think about it you could literally view this as the same thing as saying that 5 times B is equal to 20 so 5 times what is equal to 20 5 times 1 is 5 5 times 2 is 10 5 times 3 is 15 5 times 4 is 20 5 times 4 is equal to 20 so that tells us that B B must be equal to 4 B is equal to 4 so we could write 4 is equal to 20 divided by 5 which is absolutely true 20 divided by 5 is equal to 4 4 is equal to 20 divided by 5 now we have one last one we have star times 2 is equal to 4 is equal to 14 so what times 2 is equal to 14 well let's just look at our two our two are multiples of 2 so see if 2 times 1 is 2 4 6 8 10 12 14 so how did how many times we have to multiply 2 to get to 14 so this is 1 2 3 4 5 6 7 2 times 7 is 14 so if I wrote seven times 2 is equal to 14 this is absolutely true so star must be equal to 7 star is equal to 7