Divisibility Rules for Seven

The video tutorial explains a divisibility rule for the number seven. It involves taking the rightmost digit of a number, multiplying it by five, and adding the result to the remaining digits. If the new number is divisible by seven, so is the original number. The process can be repeated if necessary. The tutorial provides examples using the numbers 623 and 1,386 to demonstrate the rule in action.

What is the first step in the divisibility rule for seven?

• Multiply the rightmost digit by five

• Divide the number by seven

• Add all the digits together

• Subtract the rightmost digit

In the example of 623, what is the result after applying the divisibility rule for the first time?

• 623

• 35

• 62

• 77

Why is the number 623 considered divisible by seven?

• Because 623 is a prime number

• Because 77, the result of the rule, is divisible by seven

• Because 623 ends with a 3

• Because 623 is less than 700

What is the result after the first application of the rule on the number 1,386?

• 56

• 138

• 623

• 168

How do we confirm that 1,386 is divisible by seven?

• By checking if 1,386 is a multiple of 14

• By repeating the rule until a small number is obtained

• By dividing 1,386 directly by seven

• By adding all digits of 1,386