Grades 1-2 Video Solutions 2019-2019Levels12prob11

Video Transcription

Problem number 11. Five square cards are stacked on a table as shown. The cards are removed one by one from the top of the stack. In what order are the cards removed?  We know that all of the cards are square. That means that when a card is at the top of the stack, and therefore is the one to be removed, we will see a whole square.  I have added some dashed lines to show us where the various cards would be, to help us see better which cards are on top of them.  For card 5, we can see the whole square, so we know that it's the top card. This line shows where card 2 ends, and we can see that card 5 is the only card that's on top of card 2.  So card 2 would be the second one that needs to be moved. The bottom part of card 3 is outlined here, and we see that cards 2 and 5 are on top of it.  So once cards 2 and 5 are removed, card 3 will be the next one that we can move. Then card 1 is here. Once we have moved cards 5, 2, and 3, we can then move card 1.  Then finally, card 4 is at the very bottom. Here is what removing the cards would look like.  So the right order is 5, 2, 3, 1, 4. This is answer A.

Video Summary

The video transcript details the process of removing five stacked square cards in the correct order by observing which is visible on top at each step. The topmost card, 5, is removed first as it is fully visible, followed by card 2, since card 5 was covering it. After removing cards 5 and 2, card 3 becomes fully visible and is removed next. Card 1 is removed after cards 5, 2, and 3 are gone. Finally, card 4, at the bottom, is removed last. The correct order of removal is 5, 2, 3, 1, 4, corresponding to answer A.

Keywords

card removal

stacked cards

visibility order

correct sequence

video transcript