Question 15. John writes the numbers 1 to 4 on a sheet of paper, then he flips the sheet and writes the numbers 5 to 8 as shown. After that, he cuts the sheet into four rectangular cards and puts them in a row. What is the sum of the numbers represented by the question marks? So first, let's start off with our 1, 2, 3, 4 sheet. Since we know that John flips this sheet, when it is flipped over, it will look like this, being 2, 1, 4, 3. And on the other side, we have 6, 7, 5, 8. Now the numbers on the other side will be corresponding to the flipped sheet, like such. Now, we take a look at the four cards that are in a row. Since we know the 5 and the 6, we can erase those, and we are left with the 7 with the 1 and an 8 with the 3. Since the two cards that have question marks are black cards, we know that those numbers will be 1 and 3. So to get our answer, we just sum those two numbers together and get our answer, B, 4.

number puzzle

flipped sheet

rectangular cards

sum calculation

problem solving