- Number Sentences (Order of Operations Puzzles),
a selection of answers from the Dr. Math archives.
- Solving Number Sentences:
- I have been given a list of numbers without any plus or minus
signs and I have to place the signs between the digits.
- Order of Operations Problems -
a General Strategy
- Make equations using 7, 26, 46, and 15 to equal 160; 18, 9, 24,
and 20 to equal 18.
- A Bidirectional Search
- How can I get the numbers from 1-100 using only four 8's?
- Order of Operations Puzzle
- What is _ + _ x _ - _ = 22? We're given the numbers 2, 3, 4, 8.
- 1 2 3 4 5 6 7 8 9 0 = 100
- Leave the numerals in this order. Place only addition and
subtraction signs to make it a true statement.
- Four 4's Puzzle
- How can you get 73 by using 4 fours and any mathematical equation?
- The Four Fours - an Ancient Problem
- The problem allows you to use only four fours and as many operands
as you like in order to create mathematical sums that equal the numbers
from 1 to as high as you can go.
- Four Four's, 2-10
- Find a numerical expression using four 4s for each integer
from 2 to 10.
- Four Twos Puzzle
- How can I get 15, 17, 19 and 21 using 4 twos?
- Two 2s Make 5
- Using only two 2s and any of the standard mathematical symbols, write
an expression whose value is equal to exactly five.
- Make 24
- We have to make 24 by using 1, 3, 4, and 6.
- Make 7,7,3,3 into 24 Using + - * and /
- Make the numbers 7,7,3,3 equal 24 using the operations addition,
subtraction, multiplication, and division.
- Twenty or Fewer Steps
- Only the 1, +, -, x, /, (, ), and = keys on a scientific calculator
are working. How can a result of 75 be reached by pushing these keys
fewer than 20 times?