Open Middle®
Directions: Using the digits 1 to 9, at most one time each, place a digit in each box to make the statement true.
Hint
What is the biggest the first number could be and still be less than 10?
What can we do to avoid having a product with non-zero digits in the hundredths place?
What can we do to avoid having a product with non-zero digits in the hundredths place?
Answer
The only answer is 1.5 x 3.2 = 4.8
Source: Robert Kaplinsky with help verifying the answer from Marcia and Rick Casterline
I only found two possible answers: 1.5 and 2.5. Assumed zero was unavailable and found that placing any other digit in the tenths place created two digits to the right of the decimal point.
2.5 * 3.2 = 8.0, so if “0” is not an option, 1.5 * 3.2 = 4.8 is the ONLY answer
Neat! Thank you Marcia and Rick for figuring that out.
The answer is 1.5 x 3.2=4.8
I did this question with my grade 7s and they did quite well on it.
I gave them a follow up question of __.__ x 2.5 = __.__ There are plenty of answers for this one, but it did get them thinking on the process…
can we use the numbers in the 3.2?