Traditional Culture Encyclopedia - Photography major - The first volume of the fifth grade Olympic math problem

The first volume of the fifth grade Olympic math problem

What is the integer part of1.31.719×1.2798?

2.100×10/×102× ...×199× 200 Multiply this number 10 1. How many are there at the end of the product?

A: 0.

3.9 consecutive natural numbers, all greater than 80, how many prime numbers are there at most?