The fastest typist is Charlie at 60wpm. Let's figure out how many words he can type in 30 minutes using place value strategies.
6 * 3 = 18
Now, move the decimal two places to the right because there is one zero in 60 and one zero in 30.
1800.
Charlie can type 1800 words in 30 minutes.
The slowest typist is Jerome, at 40 wpm. Let's figure out how many words he can type in 30 minutes using place value strategies.
4 * 3 = 12
Now, move the decimal two places to the right because there is one zero in 40 and one zero in 30.
1200.
Jerome can type 1200 words in 30 minutes.
Now, subtract Charlie's words in 30 min by Jerome's words in 30 min.
1800 - 1200 = 600
Charlie can type 600 more words in 30 minutes than Jerome.
