Subtraction is the same as TAKEAWAY. When the number you are subtracting is small, you can just count backwards:
102: Think 10, 9, 8
73: Think 7, 6, 5, 4
12  1: Think 12, 11
When the number being subtracted is big, you want to count the other way.
108: Think how many MORE do I need to get from 8 to 10: 2 more
96: Think how many MORE do I need to get from 6 to 9: 3 more
When the top number is bigger than 10, we will use the BUILD TO 10 strategy.
14
7
For each number, we need to figure out how far each number is away from 10.
For our 14, the answer is EASY  as we did in the previous section we know that 10 + 4 = 14, in fact it will just be the second digit of the number: 4.
For our 7, we will use a quick and easy number chart to find out:
1 
2 
3 
4 
5 
9 
8 
7 
6 
5 
To make this table, write the numbers 1 through 5. Below the 5, write another 5 and then writing to the LEFT, continue to 9. Each pair should add to 10 if you did it right. So, if we want to find out how far 7 is from 10, we look on the chart for it's partner: 3.
Once we find the distance from 10 for both numbers, we add those two numbers together: 4 + 3 = 7 and that is our answers.
Sometimes it is easy to remember: Copy (the ones digit), Partner (use the table), and Add.
Examples: Note that the first number is just copied from the ones place, the second number is the partner from the table, then I add.
13 7

3 +3 6 
15 8

5 +2 7

14 6

4 +4 8

14 5

4 +5 9

Let's do it one step at a time together:
First how far from 10 are these numbers:
13 Answer
16 Answer
17 Answer
12 Answer
19 Answer
18 Answer
11 Answer
14 Answer
15 Answer
Use the chart to figure out how far these numbers are from 10?
2 Answer
6 Answer
5 Answer
9 Answer
7 Answer
8 Answer
1 Answer
3 Answer
4 Answer
Now to convert from a subtraction problem to an addition problem  build each to 10 and add the two numbers:
1. 14  7 Answer
2. 15 9 Answer
3. 16  8 Answer
4. 12  5 Answer
5. 15 7 Answer
6. 13  6 Answer
7. 17  9 Answer
8. 16  7 Answer
9. 14  6 Answer
10. 13  8 Answer