Answer:
5
Explanation:
The sum of 43.9 and a number is 49.65
First make equation using given phrase
Let number be x
"sum of 43.9 and a number" ⇒ 43.9 + x
43.9 + x is 49.65
Therefore, 43.9 + x = 49.65
Now solve for x
43.9 + x = 49.65 [ subtract 43.9 both sides ]
x = 49.65 - 43.9
x = 5.75
Expression:
43.9 + ?.75 = 49.65
↓
43.9 + 5.75 = 49.65
So, ? = 5
Hence, 5 will go in the box