LI: To round to estimate and approximate
Round this number to the nearest 100 and then to the nearest 1000.
Which place value columns helped you to work out your answers?
Today we will be using your rounding skills to estimate.
An estimate is not an exact answer but it is a sensible and close answer.
Have a look at this.
Luke has £3800. He wants to buy a second hand car worth £2512 and a state of the art computer worth £1963.
Can he afford it? To work this out you do not need to use the column method. Instead use rounding to help.
Round the value of the second hand car and the computer to the nearest 100.
What did you get?
Now add those together (you can do this mentally).
Does Luke have enough money to buy both items?
2500 + 2000 = 4500. He doesn't have enough money.
As you can see 4500 is not the actual amount but it is a close approximation.
Now try your questions in your work pack. :D
LI: To use the inverse operations for addition and subtraction.
Hint: Inverse means opposite and a mathematical operations are addition, subtraction, multiplication and division. :D
Challenge: Make a part whole model using these numbers 2147, 3684 and 9251. What calculations can you make with them? You would have probably used an inverse operation of another.
Take a look at this question:
? + 2496 = 8476
At first this looks challenging. You can calculate the missing number in this addition question by using the inverse operation to addition, which is subtraction.
Which subtraction calculation would you use to work this out?
8476 - 2496 = 5980
Let's check our answer.
5980 + 2496 = 8476.
Hooray, we found the answer!
Now try your questions in your work pack. :-)
LI: To solve multi-step addition and subtraction problems
Hint - Multi means multiple. So we have a few steps to do to answers one question.
Look at this:
A library has 7917 fiction book and 2468 fewer non-fiction books. There are 4708 books in the children's section. How many books are in the are in the adult section?
To calculate follow these steps:
- Find the number of non-fiction books (7917 - 2468 = non-fiction books)
- Find the total number of books in the library (fiction + non-fiction = total)
- Find the number of books in the adult's section (total books - children's section = adult's section).
Now try you work pack questions.
LI: To use addition and subtraction in real-life scenarios.
Using the knowledge you have gained in this topic complete the Lesson 4 sheets inside your work pack! Enjoy :D
The instructions are on the sheets!
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