Play the grid game from the start of the chapter, multiply four integers with the right sign, and find out why everyone gets −30240.
Preview · progress not saved — Chapter 1 is free
The rules: circle, strike out, repeat, multiply.
Round by round: −6, 14, 20 and 18, and their product.
Problem. Play the book's example and find the product. (Textbook p. 37)
Every number is a row number times a column number.
Both. The grid is a hidden multiplication table. Each row has a secret number and each column has a secret number.
Check choices and products on the magic grid.
Someone circles 8, 21, −10 and 18. Is that a legal set, and what is the product?
The magic grid for the next task.
The magic grid (Textbook p. 38). Circle one number in each row and each column, then multiply the four numbers.
Play with new numbers and report your product.
Textbook p. 38: Try again, and choose different numbers this time. What product did you get? Was it different from the first time?
Play the game on the grid shown above (8, −4, 12, −6 / −28, 14, −42, 21 / 12, −6, 18, −9 / 20, −10, 30, −15) with a choice that is not the book's example.
No two may share a row or a column.
Multiply two at a time and watch the sign.
Count the negatives you circled.
Make a new grid that always gives the same product.
Try This, Textbook p. 38: Can you make more such grids?
At least two negative.
Each cell = row number × column number.
Multiply all 8 secret numbers.