Grades 3-4 Video Solutions 2020-2020Levels34prob17

Video Transcription

Problem number 17. A standard die has seven as the sum of the dots on opposite faces. The die is put on the first square shown and then rolls toward the right.  When the die gets to the last square, what is the total number of dots on the three faces marked with the question marks? A-6, B-7, C-9, D-11, E-12. First, let's think  about the number of dots on the sides that are not shown in the original die. We know that opposite sides add up to seven. If this side shows three dots, the  side opposite it will show four. If the top has a one, the bottom will have a six. The back side will have five dots because there are two in front, but  because of the way we're rolling the die, we will never see the back side. So we already know that this number will be two. Now let's think about rolling the  die and keep track of which number is on the bottom. So if the sixth next number is three, then this number, which is one, and finally this side will end up on the  bottom. That's four. Then we're back to having six on the bottom, and after six, it's three. If we have a number three on the bottom, on the top we will have four  dots. If we look at our original die, we see that between three and four, we have one. So the one will be shown here. Now we know how many dots are shown on the  die in the last position. It's two plus one plus four, which is seven. So the answer is B, seven.

Video Summary

Summary Not Available