1001 х 21 - 420 / 6

Let's solve the expression step by step:

1. First, calculate \( 1001 \times 21 \): \[ 1001 \times 21 = 21021 \]

2. Next, calculate \( 420 \div 6 \): \[ 420 \div 6 = 70 \]

3. Now, subtract the second result from the first: \[ 21021 - 70 = 20951 \]

So, \( 1001 \times 21 - 420 \div 6 = 20951 \).