Decimals

UK Secondary (7-11)

Complete division statements to make a target number

Lesson

When we make a decimal using division, we can use the same strategies that we use with whole numbers. If we are given a list of possible solutions, we can often rule out some of the answers.

If we are looking for the answer to $5.5\div15$5.5÷15, and $12$12 is one of the possible solutions, how can we discount this as an answer? Well, we know that dividing by a number larger than $1$1 will result in smaller number, but $12$12 is larger than $5.5$5.5, so it cannot be correct. We can also use the fact that dividing by $10$10 means we have the same digits, but they are $10$10 times smaller, so our answer is $5.5$5.5.

Once we rule out some of our options, we can then use similar strategies to find the correct answer.

In our first video, we look at division that results in decimals up to tenths, using these strategies, and others, to find the correct answer.

Once we become familiar with this process, we can follow the same approach to work on division that results in answers to the hundredths. You'll see the same strategies can be used and the only difference is the value of the digits, or that more steps may be needed.

The second video shows you how to approach a problem where our answer results in hundredths.

Let’s play a game called target number. Here’s how it works: I give you a target number and starting number and you tell me what I need to get there.

For example, our target number is $0.2$0.2, and if I tell you the number $0.8$0.8 you would say $4$4, because $0.8\div4=0.2$0.8÷4=0.2.

Find the missing number below for our target number $0.1$0.1.

$0.5\div\editable{}=0.1$0.5÷=0.1

Let’s play a game called target number. Here’s how it works: I give you a target number and starting number and you tell me what I need to get there.

For example, our target number is $0.19$0.19, and if I tell you the number $4$4 you would say $0.76$0.76, because $0.76\div4=0.19$0.76÷4=0.19.

Find the missing number below if $0.13$0.13 is our target number.

$\editable{}\div7=0.13$÷7=0.13

Which of the options below make $9.18$9.18? There might be more than one right answer, so select all the correct options.

$9\div0.18$9÷0.18

A$27.84\div3$27.84÷3

B$18.36\div2$18.36÷2

C$9.18\div1$9.18÷1

D$9\div0.18$9÷0.18

A$27.84\div3$27.84÷3

B$18.36\div2$18.36÷2

C$9.18\div1$9.18÷1

D