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Carl wants to find the product 30×5/6.

Which of the following best explains how he can find the product mentally?
A.He knows that 30÷5 is 6. He then multiplies 6 by 6 to get 36.
B.He knows that 30×6/6 is 30. He then subtracts 1 from 30 to get 29.
C.He knows that 3×6=18. He then adds 18 and 5 to get 23.
D.He knows that 30×1/6 is 5. He then multiplies 5 by 5 to get 25.

User QLag
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1 Answer

2 votes

Final answer:

Carl can find the product 30×5/6 mentally by recognizing that 30×1/6 is 5 and then multiplying 5 by 5 to get 25, which is described in Option D.

Step-by-step explanation:

Carl wants to find the product 30×5/6. To do this mentally, he can use the strategy of breaking down the multiplication into simpler steps. Looking at the options presented, let's analyze how he can find the product:

• Option A suggests that Carl divides 30 by 5 to get 6 and then multiplies that by 6 to get 36. This does not relate to the original problem of 30×5/6, and thus is incorrect.

• Option B would result in subtracting 1 from 30, which is again not relevant to finding the product of 30×5/6.

• Option C involves adding 18 and 5 to get 23, which does not involve the fraction 5/6, thus is incorrect.

• Option D rightly states that 30×1/6 is 5, because 30 divided by 6 is 5. Then, multiplying 5 by 5 (since there are five 1/6ths in 5/6) will yield the correct answer, which is 25.

To conclude, the method described in Option D is the correct one, and this aligns with our understanding that multiplication involving fractions can be simplified by breaking it down into steps that are easier to perform mentally.

User Ibrahim Ulukaya
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7.7k points