The problem asks us to write the number represented by "50 millions + 207 thousands + 99 tens" in standard form with commas as per the International number system.

1. Problem Description

The problem asks us to write the number represented by "50 millions + 207 thousands + 99 tens" in standard form with commas as per the International number system.

2. Solution Steps

First, we need to calculate the value of each part:

50 millions = $50,000,000$

207 thousands = $207,000$

99 tens = $99 \times 10 = 990$

Next, we sum these values:

$50,000,000 + 207,000 + 990 = 50,207,990$

Finally, we write the number with commas according to the International number system: $50,207,990$.

3. Final Answer

50,207,990