Question

15 + 21 = 3 (4 + 8)

What is Aida’s error?
Aida used 3 as the factor, which is not common to 15 and 21.
Aida did not correctly divide by the common factor to get (4 + 8).
Aida did not apply the correct operations to the expressions.
Aida wrote two expressions that are not equivalent.

Answer 1

B). Aida did not correctly divide by the common factor to get (4 + 8).

Explanation:

Aida applied the distributive property to write the equivalent expressions given as

15 + 21 = 3(4 + 8)

But Aida made a mistake.

Since to get the common factor of 15 and 21 she did not divide these numbers by 3 correctly.

In simple words by division of 3 in 15 and 21, we get 5 and 7 instead of 5 and 8.

Therefore, Aida did not correctly divide by the common factor to get (4 + 8). ⇒ option B is the correct answer.

Answer 2

Aida did not correctly divide by the common factor to get (4 + 8).