Today's concept covers a variety of operations and levels of difficulty, but it is can be handled successfully with careful attention to the details. It has appeared 9 times on elementary tests so far this year, with a median placement at question # 59.
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Number Dojo Level: 205
I approach these problems with two general steps:
- Translate them into "math language."
- Solve for X like any other algebra problem.
To translate the problems into math language, use the following substitutions:
- "what" or "the number": X
- "is" or "equals": =
- "more than": +
- "less than": -
Example 1: 8 plus what equals 17? ___
- Translate this to: 8 + X = 17
- Subtract 8 from both sides to find that X = 9
Example 2: 26 minus what equals 19? ___
- Translate this to: 26 - X = 19
- Subtract 26 from both sides to find that -X = -7, so X = 7
Example 3: If two times a number is four more than the number, what is the number? ___
- Translate this to: 2X = 4 + X
- Subtract X from both sides to find that X = 4
Example 4: If three times a number is ten more than twice the number, what is the number? ___
- Translate this to: 3X = 10 + 2X
- Subtract 2X from both sides to find that X = 10
Example 5: What number times 4 and subtracted from 45 gives the same result? ___
- Translate this to: 4X = 45 - X
- Add X to both sides to find that 5X = 45; X = 9