Final answer:
To solve 5 + 7, recognize the related doubles fact 7 + 7 which equals 14. Since 5 is two less than 7, subtract two from 14 to get 12.
Step-by-step explanation:
The question asks which doubles fact can help you solve the addition problem 5 + 7 = 12. A doubles fact in mathematics is an equation where the two addends are the same. These facts are very useful because they are easy to remember and can assist in solving more complex problems. For example, the doubles fact for 7 is 7 + 7 = 14. Knowing this, we can realize that 5 + 7 is close to 7 + 7 but is 2 less, because 5 is 2 less than 7. By subtracting 2 from the sum in the doubles fact (14 - 2), we get 12, which is the correct answer for 5 + 7.