Thinking of solving problems: Four arithmetic rules (calculation in sequence, first multiplication and division, then addition and subtraction, first parenthesis, first power), that is, disjoint operation (recursive equation calculation), should be carried out on the premise of this principle.

Problem solving process:

5× 15×25× 125×64

=(5×2)×(25×4)×( 125×8)× 15

= 10× 100× 1000× 15

= 15000000

Expand data (vertical calculation-calculation process): first align the last digits of two multipliers, then use the second multipliers respectively, multiply each digit by one multiplier in turn from the last digit, and finally accumulate the calculation results into a product. If the multiplier is decimal, the corresponding multiple can be expanded first, and then the product can be reduced by the corresponding multiple;

Problem solving process:

Step 1: 5×8=40

Step 2: 2×8= 160

Step 3: 1×8=800

According to the above calculation results, the total is 1000.

If in doubt, please ask questions. If satisfied, please adopt them.