Encoding pictures – practice for Years 4–6

Sample questions on Encoding pictures with the right answer and a worked solution, from easy to hard. In the Pickles Academy app a child gets new questions of the same kind every time, so they can't just learn the answers by heart.

Subject

Computing

Year

Years 4–6

Curriculum area

Data, information and modelling

Question types: A picture as numbers

Sample questions

1. Question 1 Easy

   A picture is written row by row as numbers: how many white squares in a row, then how many coloured, then white… Each row starts with the number of white squares (it may be 0). What is the code of row 2 of the picture?

   1. A) 0, 4, 1, 1
   2. B) 4, 1, 1
   3. C) 1, 3, 1, 1
   4. D) 0, 1, 2, 1, 2
   5. E) 1, 1, 4, 0
   Show the solution

   Answer: A) 0, 4, 1, 1

   How it works: Row 2: 0, 4, 1, 1.

2. Question 2 Normal

   A picture is written row by row as numbers: how many white squares in a row, then how many coloured, then white… Each row starts with the number of white squares (it may be 0). Which row of the picture has the code 2, 1, 2, 1, 1?

   1. A) row 1
   2. B) row 2
   3. C) row 3
   4. D) row 4
   5. E) row 5
   Show the solution

   Answer: C) row 3

   How it works: 1: 0, 1, 2, 1, 2, 1; 2: 0, 3, 1, 1, 2; 3: 2, 1, 2, 1, 1; 4: 1, 3, 3; 5: 2, 1, 3, 1

3. Question 3 Hard

   A picture is written row by row as numbers: how many white squares in a row, then how many coloured, then white… Each row starts with the number of white squares (it may be 0). The picture has 8 columns and 6 rows; each line of the code is one row. How many squares are coloured?

   10, 1, 2, 1, 2, 2
   20, 2, 1, 1, 4
   30, 1, 2, 1, 2, 2
   40, 1, 5, 1, 1
   52, 1, 2, 1, 2
   63, 2, 1, 1, 1
   

   Show the solution

   Answer: 18

   How it works: The 2nd, 4th, 6th … numbers of each row are coloured: 4 + 3 + 4 + 2 + 2 + 3 = 18.

All Computing topics