1. Find 93 * 87 using mental math.
A- 8091
B- 8079
C- 8121
D- 7221
81
To find the product of 93 and 87 using mental math, you can use the method of multiplying numbers using their differences from a base. Here's how you can do it:
Step 1: Find the difference between each number and the base of 100.
- 93 is 7 less than 100, so its difference is -7.
- 87 is 13 less than 100, so its difference is -13.
Step 2: Add the differences to the base and multiply them together.
- (100 - 7) * (100 - 13) = 93 * 87
Step 3: Simplify the expression.
- (100 - 7) * (100 - 13) = (100 - 20) * (100 - 13) = 80 * 87
Step 4: Use mental math to multiply 80 by 87.
- 80 can be split into 8 * 10.
- Multiplying 87 by 8 gives 696, and then multiplying 696 by 10 gives 6960.
Step 5: The final answer is 6960.
Therefore, the correct answer to the question is not listed among the options provided. The correct answer is not A (8091), B (8079), C (8121), or D (7221). The correct answer is 6960.