**Problem Solving 56**

Our four step

For multi-step problems you will need to work through this process more than once.

The canteen at

Keywords / information: how many lunches ordered that week, 204, twenty three more, 198

Irrelevant information: popular, makes money, last week of Term 1

We need to work out how many lunch orders altogether, so we need to add. As we only know the number of lunches ordered on Monday and Friday, we firstly need to calculate the number of lunches ordered on Wednesday. That means we need to work through the

**ROCS**approach:**ead - the question carefully. Underline the keywords / information and ignore any irrelevant information.****R****peration - what operation do you need to solve the problem? Do you need to add, subtract, multiply or divide?****O****alculate the answer.****C****ense - does your answer make sense? If it does, you're probably correct. If not, work through the process again.****S**For multi-step problems you will need to work through this process more than once.

**Word Problem 1**The canteen at

*Westdale Primary School*is very popular with the students and makes a lot of money for the school. It opens three days a week. In the last week of Term 1, 204 children ordered lunches on Monday, twenty three more children ordered lunches on Wednesday and 198 children ordered lunches on Friday. How many lunches were ordered that week?**R**eadKeywords / information: how many lunches ordered that week, 204, twenty three more, 198

Irrelevant information: popular, makes money, last week of Term 1

**peration****O**We need to work out how many lunch orders altogether, so we need to add. As we only know the number of lunches ordered on Monday and Friday, we firstly need to calculate the number of lunches ordered on Wednesday. That means we need to work through the

**process again to identify the keywords that will enable us to calculate that figure.****ROCS**

**Wednesday's Lunch Orders**

**ead****R***Keywords / information: twenty three more*

**peration****O***The word*

__more__means we need to add.

**alculate****C***204 + 23 = 227*

**ense****S***The answer needs to be 23 more than 204 and makes sense.*

**alculate**

**C**We now know the number of lunches ordered on each of the three days, so we can add them together.

204 + 227 + 198 = 629

**S**ense

The number of lunches ordered on each of the three days is over or just under 200.

As 3 x 200 = 600, the answer makes sense.

Try our easier word problems quiz below and look out for our average and harder word problems coming soon.

**Word Problem 2***We live in an old house so my father wanted to make new curtains for all of our bedrooms. If he needed 6 metres of curtain material for the master bedroom and 4 metres of curtain material for my brother's bedroom and my bedroom, how much would the curtain material cost altogether if it is $20 per metre?*

**R**ead

Keywords / information: how much cost altogether, 6m, 4m, 4m, $20/m

Information that is not important: old house, master bedroom, brother's bedroom, my bedroom

**O**peration

We need to calculate the total cost, so we need to multiply. Before we can multiply we need to know how many metres altogether. We need to work through our ROCS approach again to make that calculation.

**How much curtain material?**

*R**ead*

*Keywords / information: 6m, 4m, 4m*

**peration****O***We need to know how many metres altogether, so we need to add.*

**alculate****C***6 + 4 + 4 = 14*

**ense****S***6 and 4 are best friends to 10 and we need to add 4 more. It makes sense.*

**alculate**

**C**We can now multiply to work out the total cost: 14 x $20 = $280 (14 x 2 = 28 and add a zero)

Our answer is $280.

**ense**

**S**As 10 x $20 = $200, our answer needs to be more than $200. With another 4 x $20 still needing to be added, our answer makes sense.