Maths

Division (Problems)

Today we are going to look at using division with word problems (the type you will get in the SATS).

Before we do let us look back on the things we have covered:

1.                    We have looked at simple division

2.                    We have looked at problems that involve remainders

3.                    We have looked at fractions and how we deal with them. We have then dealt with fractions in          division.

4.                    We have looked at inverse (opposite) operations and used these to check our answers

Now we need to use all of this in solving problems.

Here is an example.

A man has a box of 288 pens and he shares the pens out equally amongst 4 children. How many pens does each child get?

Here we have to break up 288 into 4 equal parts.

So how would we write this down? Did you get this? If you did well done.

Now to solve it:

How many 4's in 2 (none)

How many 4's in 28? (7) No remainder

How many 4's in 8? (2) Remember that multiplication is the inverse (opposite) of division so multiply your answer to see if you get back to your question.

4 X 72 = 288 (our answer is right)

A man has a box of 288 pens and he shares the pens out equally amongst 4 children. How many pens will each child receive?

Each child will receive 72 pens.

Here are a few to practise. I have put the answers with the working out for these just to show you how they work.

Questions

1.         Music CDs cost £3 each. David has got £258 from the school to buy new CDs for the disco.

2.            (a) Lorna has got a ribbon 458cm long how many pieces of 8cm can be cut from it? (b) How much is remaining

3.             A school trip consists of 45 children and 8 adults.
(a) How many taxis are needed to take them to their destination if each car can carry four people?
(b) How many taxis will be needed if each taxi could carry 5 people?

4.          Find the missing number 4 X =204

1. David can buy 86 CDs

2.        (a) Lorna can cut 57 pieces of 8cm from the ribbon
(b) a piece of  2cm is left over

3.        (a)   45 + 8 = 53 They need 14 taxis (13 taxis will leave 1 person behind) So 14 is the least number of taxis they need.

(b)     If each taxi can carry five people They will need 11 taxis (10 will leave 3 behind)

4         The missing number is 51 (remember that multiplication is the opposite of division).
So we can use division to solve multiplication problems when we are missing part of the question.

Review

Well how did you do?

I hope you thought about the third question. It doesn’t make sense to talk about decimals when dealing with many real objects because we can not break them into pieces.

Here are 3 more questions to finish off.

1.             Find the missing number    7 X  ?   = 91

2.             Find the missing number    ?  ÷ 13 = 21

3.             Find the missing number 747 ÷  ?  = 249

1.             Find the missing number 7 X 13        = 91         (13)

2.             Find the missing number    273 ÷ 13 = 21        (273)

3.             Find the missing number 747 ÷3= 249              (3)

Well that is enough for today. How did you find that?

I hope that you are feeling more positive about being able to solve problems with division

Review.

Today:

We looked at dealing with problems using division.

We have also looked at using inverse (opposite) operations to solve problems.

We have covered using remainders. When and when not to count them.