 Solve problems with mixed operations II

Lesson

When we want to solve a problem that is given to us in words, it can help to write it out as a number problem.  Finding the numbers we need, and how we treat those numbers, helps us solve the problem more easily.

Written problems give us clues as to the types of mathematical operations we may need.  For example:

• if we need to add, the problem might use words like more or extra
• if we need to subtract, the problem might use words like less or gave away
• if we need to multiply the problem might say groups of
• if we need to divide the problem might say share.

There are many other types of words that occur in problems. As you watch this video, take note of the words and what operation they connect to.  Can you think of others?

Worked examples

Question 1

Laura has saved $£60$£60 over the course of the last month. If she earns $£10$£10 this week from doing chores, and finds another $£20$£20 while out for a walk, how much does she have?

question 2

Write a division number sentence to match the word problem.

You do not need to solve the question.

1. A lecture hall has $391$391 seats. Each row has $17$17 seats. How many rows of seats are there?

question 3

Miss Oakley has $37$37 chocolates to give out to $3$3 groups of students on a school excursion.

She firstly takes away $4$4 chocolates to save for students who are absent, then she divides the remaining chocolates equally among the $3$3 groups.

1. If $N$N stands for the number of chocolates each group receives, find $N$N.