Addition, page 2
Now, let's look at the symbols.
When we have a problem that has small numbers like 3 and 4 and 7, it is easy to use the integer bars. What happens, though, when we have larger numbers? Maybe we should try to find a symbolic way to think about this.
We put the 7 bar down and we put the 3 bar down. We ask ourselves what is missing?
Can we think of that as 7 - 3 = x? It is easy to see that our answer is 4.
Let's look at that yet another way:
Can you use that method with the other problems?
x + 2 = 6 y + 10 = 12 a + 2 = 9
Once you have tried them, look here to check your answers.
Here's one more problem to try using the symbolic method:
x + 22 = 36
Once you have tried it, look here to check your answer.
The Ask Dr. Math Archives have letters from students with answers from math doctors. Here are some selections on this topic:
Two Ways to Solve an Equation
Solve for x: x + 3 = 7
Solving Simple One-variable Equations
Solve for n: n + 39 = 12