Group Work - Remainder Operator (%)

Group Work - Remainder Operator (%)

Each coding exercise has its own folder. Open its .java file and press Run to try it.

It is best to use a POGIL approach with the following. In POGIL students work in groups on activities and each member has an assigned role. For more information see https://cspogil.org/Home. This page is based on a POGIL activity from Helen Hu at that site.

Look at the expressions in the code above and the output. Then answer the following questions.

Exercise 1

Run the code to see what it prints.

Open the 01-mod-model-1 folder and run ModModl1.java. It is an example, so it has no tests.

Check your understanding: Review the code in 01-mod-model-1. What is the first number (n) such that n % 4 returns zero? — answer it on CS Awesome: https://runestone.academy/ns/books/published/csawesome2/group-mod-practice.html#mod-which-returns-zero

Check your understanding: Review the code in 01-mod-model-1. What is the next number (n) (greater than 16) such that n % 4 returns zero? — answer it on CS Awesome: https://runestone.academy/ns/books/published/csawesome2/group-mod-practice.html#mod-next-returns-zero

Going Beyond Remainder 4

Check your understanding: What is the first number from 1 to 10 that is evenly divisible by five (n % 5 returns 0)? — answer it on CS Awesome: https://runestone.academy/ns/books/published/csawesome2/group-mod-practice.html#mod-return-zero-mod-five

Check your understanding: What is the last number from 1 to 10 that is evenly divisible by five (n % 5 returns 0)? — answer it on CS Awesome: https://runestone.academy/ns/books/published/csawesome2/group-mod-practice.html#mod-return-zero-mod-five-last

Look Deeper

Look at the code above for the numbers such that n % 4 returns 1. How do these numbers differ from the ones that return zero?

Discuss this with your class, or answer it on CS Awesome: https://runestone.academy/ns/books/published/csawesome2/group-mod-practice.html#mod-returns-one-sa

More Practice

Check your understanding: What is the number returned from 18 % 4? — answer it on CS Awesome: https://runestone.academy/ns/books/published/csawesome2/group-mod-practice.html#mod-18-mod-4

Check your understanding: What is the number returned from 19 % 4? — answer it on CS Awesome: https://runestone.academy/ns/books/published/csawesome2/group-mod-practice.html#mod-19-mod-4

Check your understanding: What is the number returned from 19 % 5? — answer it on CS Awesome: https://runestone.academy/ns/books/published/csawesome2/group-mod-practice.html#mod-19-mod-5

Check your understanding: What is the number returned from 19 % 6? — answer it on CS Awesome: https://runestone.academy/ns/books/published/csawesome2/group-mod-practice.html#mod-19-mod-6

Long Division with a Remainder

Consider how you did long division in elementary school where you determined what number goes evenly into another number and the remainder.

Check your understanding: What number is the remainder when you divide 79 by 5? — answer it on CS Awesome: https://runestone.academy/ns/books/published/csawesome2/group-mod-practice.html#mod-79-mod-5

Dividing Evenly

Imagine if you were given candies to evenly divide amoung members of a group of four people. Follow kindergarten rules where every group member gets the same number of candies and the extras go back to the teacher.

Check your understanding: How many candies go back to the teacher when you are given 11 candies? — answer it on CS Awesome: https://runestone.academy/ns/books/published/csawesome2/group-mod-practice.html#mod-11-mod-4

Check your understanding: How many candies go back to the teacher when you are given 2 candies? — answer it on CS Awesome: https://runestone.academy/ns/books/published/csawesome2/group-mod-practice.html#mod-2-mod-4

Describe the Remainder (%) Operator

Describe what % does in your own words. Use complete sentences.

Discuss this with your class, or answer it on CS Awesome: https://runestone.academy/ns/books/published/csawesome2/group-mod-practice.html#mod-describe-mod-sa