Skill: Read whole numbers to the millions

To read a whole number to the millions, group its digits into periods of three, starting from the right:

• Millions period
• Thousands period
• Ones period

Each period can have up to three digits.

Example: Read $(407{,}032{,}015)$.

1. Separate the number into periods:

$$407\mid032\mid015$$

So the number has:

• $(407)$ millions
• $(032)$ thousands
• $(015)$ ones

2. Read each period from left to right:

   • $(407)$ is four hundred seven million.
   • $(032)$ is thirty-two thousand. Do not say “zero thirty-two.”
   • $(015)$ is fifteen. Do not say “zero fifteen.”

3. Put the parts together:

$$\boxed{\text{four hundred seven million thirty-two thousand fifteen}}$$

The zeros are placeholders. They keep the digits in their correct places, even though they are not spoken.

The expanded notation shows the value of each nonzero digit:

$$407{,}032{,}015 = 400{,}000{,}000+7{,}000{,}000+30{,}000+2{,}000+10+5$$