How does the divisibility rule for 4 and 8 work?

Answer 1

A number is a multiple of 4 if the last 2 digits are a multiple of 4

• The 10s digit is even and the last digit is 0, 4 or 8
• The 10s digit is odd and the last digit is 2 or 6

A number is a multiple of 8 if the last 3 digits are a multiple of 8

• The 100s digit is even and the last 2 digits are a multiple of 8
• The 100s digit is odd and the last 2 digits are 4 times an odd number

Answer 2

why does the divisibility rule work for 4