Concept
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One difficult type of Algebra problem are word problems asking about the sum of digits in a two digit number. Solving systems of equations by substitution is one of the most common ways to solve sum of digits problems. Other types of word problems using systems of equations include mixture problems, money word problems, work word problems and rate word problems.
Sample Problems
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Need help with "Sum of Digits" problems? Watch expert teachers solve similar problems to develop your skills.