Open Middle®
Directions: Using the digits 1 to 9, at most one time each, place a digit in each box to create an equation using addition and subtraction that equals 4.
Hint
Where might thinking about odd and even numbers help with placement?
How does thinking about the relationship between denominators help you with this problem?
How does thinking about the relationship between denominators help you with this problem?
Answer
There are 360 possible solutions. Two examples are 5 2/3 + 7 4/8 – 9 1/6 and 5 6/8 + 7 3/4 – 9 1/2.
Source: Erik Almer
5 2/3 + 7 4/8 – 9 1/6
9 5/6 + 1 2/3 – 7 4/8
Whoa, there are seriously 360 answers to this question??
1 1/3 + 2 3/3- 1/3
1 1/3 + 2 3/3- 1/3 cool way>
=1/3
3 1/3+ 3 + 3 1/3 – 2 2/3 = 4
5 2/3 + 7 4/8 – 9 1/6
Hi