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Example 1.13 from Prealgebra, 1.2 Add Whole Numbers
Add Whole Numbers: example 1.13
Model the addition
Work it out on paper first. Then open the solution one step at a time, and stop as soon as you can finish on your own.
Solution
means the sum of and
Each addend is less than 10, se we can use ones blocks. Model the first number with 5 blocks. Model the second number with 8 blocks. Count the result. There are more than 10 blocks so we exchange 10 ones blocks for 1 tens rod. Now we have 1 ten and 3 ones, which is 13. 5 + 8 = 13 Notice that we can describe the models as ones blocks and tens rods, or we can simply say ones and tens. From now on, we will use the shorter version but keep in mind that they mean the same thing.
Your turn
The book's Try It right after this example: same idea, new numbers. Only the answer is given.
Model the addition:
How did it go?