Equations

Puzzles

• 1234Using the digits 1, 2, 3 and 4 once each, with various sets of allowed operations, how far can you form... New
• 123456789In how many ways can "." be replaced with "+", "-", or "" (concatenate) in .1.2.3.4.5.6.7.8.9=1 to form a...
• 19921 = -1+9-9+2. Extend this list to 2 through 100 on the left side of the equals sign.
• 1994Write as many numbers as possible, from 0 upward, using only the digits 1, 9, 9 and 4, each exactly once... New
• 1997Use the four digits 1, 9, 9, 7, in that order, with additions, subtractions, multiplication, division,... New
• 24Form an expression that evaluates to 24 that contains two 3's, two 7's, and zero or more of the operators +, -, *, and /, and parentheses.
• 383Make 383 out of 1,2,25,50,75,100 using +,-,*,/.
• findWrite a program for finding expressions built out of given numbers and using given operators that evaluate...
• four.4Form expressions equalling each integer from 1 to 112 from four 4's, which may be concatenated to form a... Added material
• make.threeFor each digit from 1 to 9, use that digit three times, with arithmetic operations, to make 3. New
• own.digitsFind all 3-digit numbers that can be formed from their own digits. New
• ten.digits.sum.100Using each of the ten digits 0 through 9 exactly once, and only addition and concatenation (e.g. New
• ten.digits.sum.productUsing the digits 0-9, each only once, construct A+B=C. New, unsolved