Find the Missing Terms in Addition Sequence: 40+52 to 12+28

To solve this problem, we'll analyze the given sequence's patterns:

First, let's observe the sequences:

$40 + 52$

$? + ?$

$26 + 40$

$19 + 34$

$12 + 28$

Let's determine any consistent changes for the first numbers $(40, 26, 19, 12)$ and the second numbers $(52, 40, 34, 28)$.

Notice for the first numbers:
$40$ becomes $26$ which decreases by $14$,
$26$ becomes $19$ which decreases by $7$,
$19$ becomes $12$ which also decreases by $7$.

For the second numbers:
$52$ becomes $40$ which decreases by $12$,
$40$ becomes $34$ again decreasing by $6$,
$34$ becomes $28$ decreasing by $6$.

The pattern therefore for the first number decreases by $7$ for the second and third pairs; the second number decreases by $6$.

We can conclude the missing sequence is:

• The first sequence element should be $33$ computed as $40 - 7 = 33$.
• The second sequence element should be $46$ computed as $52 - 6 = 46$.

Therefore, the correct answer is $33 + 46$, which matches choice 3.

In conclusion, the missing sequence element that fits the pattern is $33 + 46$.