Now that we have taken our journey through the middle school and high school number sense tests, I thought I should get back to the basics and help the "young-uns" with the beginner concepts. This blog will now alternate between elementary, middle, and high school concepts. But instead of covering 10 concepts in a row from the same difficulty level (questions 1-10, 11-20, 21-30, etc.), I'll just do one at a time. In other words, today's post will be from questions 1-10, and my next elementary school post will come from questions 11-20. Also, I will address the most common questions from this year's tests that haven't already been covered previously.
Questions with expanded notation have appeared 5 times so far this year on elementary tests with a median placement at question # 6.
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Number Dojo Level: 3
One way to represent today's concept is to think about how we "read" numbers (either in our minds or aloud). For example, the number 1974 reads "one thousand nine hundred seventy-four." Or we could think of it as:
Example 1: (6 x 100) + (8 x 10) + (2 x 1) = ___
- This is 600 + 80 + 2.
- The answer is 682.
Example 2: 4 x 1000 + 5 x 100 + 3 x 1 = ___
- This is 4000 + 500 + 3.
- The answer is 4503. (Notice there were no tens in there).
Example 3: (6 x 100) + (7 x 10) - (3 x 1) = ___
- This is 600 + 70 - 3. (Notice the subtraction).
- This becomes 670 - 3, which is 667.