Order of operations and simple expressions - 4th grade math
In this 4th grade math lesson we deal with parenthesis and the four operations — no exponents or roots yet. This is basically review of some of what students have learned in Math Mammoth grade 3. I enclose the operation to be done first in a "bubble". Children can use various colors to do this!
Next, we write simple expressions (number sentences) from the verbal description, using several operations and parenthesis. In other words, we need to take into account the order of operations here! For example, subtract 12 and 6, and multiply the result by 4.... one needs parenthesis to make sure the subtraction happens BEFORE multiplication. If you write 12 − 6 × 4, the multiplication would be done first according to the order of operations. Therefore, the right answer is either 4 × (12 − 6) or (12 − 6) × 4.
Lastly, we get to solve some puzzles where the operation signs are missing. Mathy my mascot mammoth is of course excited about that!
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See also
Bar models in addition and subtraction — video lesson
Math Mammoth Grade 4 curriculum