Question

Write the number in scientific notation.
In a certain city, the subway system carried a total of 1,890,000,000 passengers

Answer 1

1.89x10^9, just count the number of decimal places

Answer 2

10^1=10
10^2=100
10^3=1000
10^4=10000
10^5=100000
...
1,000,000,000=10^9
1890,000,000=1.89*10^9