Often, word problems appear confusing, and it is difficult to know where to begin. Here are some steps that will make solving word problems easier:
- Read the problem.
- Determine what is known and what needs to be found (what is unknown).
- Try a few numbers to get a general idea of what the solution could be.
- Write an equation.
- Solve the equation by inverse operations or by plugging in values.
- Check your solution--does it satisfy the equation? Does it make sense in the context of the problem? (e.g. A length should not be negative.)
Example 1: Matt has 12 nickels. All the rest of his coins are dimes. He has just enough money to buy 2 slices of pizza for 95 cents each. How many dimes does he have?
- Read the problem.
- What is known? Matt has 12(5) = 60 cents in nickels. Matt has 2(95) = 190 cents total. What needs to be found? The number of dimes that Matt has.
- Try a few numbers:
5 dimes? 10(5) + 60 = 110. Too low.
10 dimes? 10(10) + 60 = 160. Still too low.
20 dimes? 10(20) + 60 = 260. Too high.
So we know the answer is between 10 and 20.
- Write an equation: 10d + 60 = 190 where d is the number of dimes Matt has.
- Solve using inverse operations:
10d + 60 - 60 = 190 - 60
10d = 130
= 
d = 13 - Check: 10(13) + 60 = 190? Yes. Does 13 dimes make sense in the context of the problem? Yes.
Thus, Matt has 13 dimes.
Diagram of a Square
Example 3: The area of this square is 2 times its perimeter. How long is a side?
- Read the problem.
- What is known? The area of the square is 2 times its perimeter. The formula for area is A = x2 and the formula for perimeter is p = 4x. What needs to be found? The length of a side.
- Try a few numbers:
x = 5? A = 52 = 25, p = 4(5) = 20. Area too small.
x = 10? A = 102 = 100, p = 4(10) = 40. Area too large.
So we know the answer is between 5 and 10.
- Write an equation: x2 = 2(4x). x2 = 8x
- Solve by plugging in values----or by using inverse operations:
= 
x = 8 - Check: 82 = 8(8) ? Yes. Does 8 make sense in the context of the problem? Yes.
Thus, the square has side length 8.