 Algorithms for Divisibility

Interactive practice questions

To test whether a number is divisible by $10$10, we use the following simple algorithm.

"If the number ends in a $0$0, then the number is divisible by $10$10."

a

Examine the following list of three-digit numbers and write down all the numbers that are divisible by $10$10.

Write these numbers on the same line, separated by commas.

$313,882,710,170,479,381,860,465,256,344$313,882,710,170,479,381,860,465,256,344

b

Examine the following list of five-digit numbers and write down all the numbers that are divisible by $10$10.

Write down these numbers on the same line, separated by commas.

$42381,92176,86498,59433,24499,21880,95534,61110,25190,39137$42381,92176,86498,59433,24499,21880,95534,61110,25190,39137

c

Examine the following list of seven-digit numbers and write down all the numbers that are divisible by $10$10.

Write down these numbers on the same line, separated by commas.

$6459620,5638943,2878605,1904790,5037628,6805217$6459620,5638943,2878605,1904790,5037628,6805217

Easy
Approx 2 minutes

To test whether a number is divisible by $2$2, we use the following simple algorithm.

"If the number is even (that is, the digit in the ones column is even), then the number is divisible by $2$2."

To test whether a number is divisible by $5$5, we use the following simple algorithm.

"If the number ends in a $0$0 or a $5$5, then the number is divisible by $5$5."

To test whether a number is divisible by $3$3, we use the following algorithm.

Step 1: Find the sum of the digits of the number.

Step 2: If the sum is a multiple of $3$3, then the number itself is a multiple of $3$3.

Use the algorithm to determine whether $34257$34257 is divisible by $3$3.