Lesson

Now that we've seen how to tackle written addition and subtraction problems that have two steps, we can build on our skills to work up to problems with more steps. The process is identical, but we have more steps to work through. There can be information that we don't need as well, so be sure to read through and highlight the important information.

In Video 1, we work through a problem with three parts, then we make some small changes to see how we can solve the problem a different way.

We need to follow the order of operations, but if we only have addition and subtraction, we can vary the order. If we have an idea to make it a little easier to solve. In our next video, we look at a problem with addition and subtraction. By looking at the water level in the rain gauge, we also get to see why it is possible to add and subtract in a different order.

Careful!

You can change the order of your problem when you have only addition and subtraction, but remember if you have any multiplication or division, these parts must be solved first.

A retail store has sold $241$241 of their branded t-shirts over the last $9$9 months and is expected to sell $14$14 t-shirts in the next month, $69$69 t-shirts in the following month and $35$35 t-shirts in the month after that. In addition, the store has also sold $50$50 branded shorts in the last month.

If the store meets their expected sales in the next three months, how many branded t-shirts will they have sold over the last year?

Mohamad currently has $\$876$$876 in his savings account. His work deposits $\$457$$457 into his savings account and later he spends $\$55$$55 on lunch with a friend and $\$99$$99 on groceries, which he withdraws from his savings account.

How much money is left in Mohamad's savings account?

An editor at a filming studio is editing some film. The unedited video is $211$211 minutes long. She cuts out the first $32$32 minutes, where she was doing some video testing. She then cuts out $32$32 minutes of film where the audio's volume was low. Lastly she cuts out $32$32 minutes worth of footage where she was still filming between takes.

How long is the edited footage?

Solve problems that arise from real-life situations and that relate to the magnitude of whole numbers up to 100 000

Solve problems involving the addition, subtraction, and multiplication of whole numbers, using a variety of mental strategies (e.g., use the commutative property: 5 x 18 x 2 = 5 x 2 x 18, which gives 10 x 18 = 180)