Final answer:
The equation '64 - 7 = 57' uses the ten which is 60 because it is a multiple of ten close to 64 that simplifies mental arithmetic. Understanding multiples and powers of ten is beneficial in various mathematical problems, such as performing subtraction easily and using scientific notation.
Step-by-step explanation:
The equation 64 - 7 = 57 is a simple subtraction problem. To understand which ten is being used, it is helpful to recognize that the number 64 is close to the multiple of ten which is 60.
When doing mental math, this proximity to a 'round number' makes calculations easier because it simplifies the problem to 60 - 7 = 53, plus the remaining 4 that was not part of that 'round number', resulting in 57.
In the provided reference material, there are several instances where powers of ten are used to simplify or conceptualize problems, such as in scientific notation. For example, a number like 1,372,568 becomes 1.372568 times a million (106), emphasizing the importance and convenience of understanding powers of ten in mathematics. Therefore, recognizing and using multiples of ten is a very helpful skill in various mathematical contexts, including basic arithmetic and scientific notation.