Arrays

Lesson Plan - Get It!

Audio:

• What type of problem did you create to go along with the image above?

Maybe, you created a numerical problem, or maybe you created a word problem.

• What operation did you use?

Show your problem to a teacher or parent and explain your reasoning.

Most likely, you created a multiplication problem to quickly determine the number of cookies on the sheet. Whether you created a numerical or a word problem, you probably used 3 x 5 or 5 x 3 in the problem to represent three columns and five rows, or five rows and three columns, of cookies. The image is an example of an array, and arrays are used to represent multiplication problems.

Multiplication is just a way to simplify long addition problems. For example, if Mrs. Jones has three children and each child gets five cookies after dinner, you could say 5 + 5 + 5 = 15. To simplify this problem, you could say 3 x 5 = 15. You could also use the array at the beginning of the lesson to illustrate the problem.

Arrays, like the one at the beginning of the lesson, can also be used to represent multiplication problems and word problems involving multiplication.

When you look at an array, you need to know the difference between a row and a column. A row runs horizontally and a column runs vertically.

• How many rows make up the array? 
• How many columns make up the array?

Share and explain your answer to a teacher or parent.

• Did you say there are three rows and five columns?

That is the correct answer. To find the total number of objects that make up an array, multiply the number of rows by the number of columns. Tell your teacher or parent how many cookies make up this array. 3 x 5 = 15. Therefore, 15 cookies are a part of this array.

• Think you understand how and why arrays work?

Move on to the Got It? section to practice creating arrays and solving problems with arrays.