Dividing by Five
In this video, we will learn how to
divide by five using models and the five times table. When we’re dividing by five, it
really helps to know your five times table. So, let’s practice reciting the
five times table. One times five is five. Two times five is 10. Three times five is 15. Four times five is 20. Five fives are 25. Six times five is 30. Seven fives are 35. Eight fives are 40. Nine times five is 45. And 10 fives are 50.
We can use these times table facts
and models like this array to help us divide by five. For example, if we want to divide
35 by five, we could use the array. The counters have been placed in
columns or groups of five. We need to work out how many fives
there are in 35. Five, 10, 15, 20, 25, 30, 35. How many times did we count in
fives? One, two, three, four, five, six,
seven. There are seven fives in 35. If we know that seven times five is
35, we can use this fact to help us find 35 divided by five. We know that seven fives make
Another way we can divide by five
is to use a number line. Each division on the number line is
worth five. That means we’re skip counting by
five. How can we find 45 divided by five
using this number line? We need to skip count by fives and
count the number of jumps we make to reach the number 45. We’ve already made one jump from
zero to five. Two fives are 10. Three fives are 15. Four fives are 20. Five fives are 25. Six fives are 30. Seven fives are 35. Eight fives are 40. And nine fives are 45. There are nine fives in 45. 45 divided by five equals nine.
Another way we could use our number
line to find 45 divided by five is to start at 45 on the number line. We need to count back in fives
until we reach zero. We’ve already counted back one lot
of five. Two, three, four, five, six, seven,
eight, nine. So, when we’re dividing by five, we
can count forward in fives or count back in fives. We’ve also learned that we can use
arrays to help us divide by five. We found 35 divided by five by
counting the number of groups there are in 35. We’ve also practiced our five times
table to help us divide by five. We can find 40 divided by five if
we know that five times eight equals 40. Let’s practice the strategies we’ve
learned to divide by five by answering some questions now.
What is 20 divided by five?
In this question, we have to
calculate 20 divided by five, and we’ve been given this array to help. Each row in the array contains five
counters: five, 10, 15, 20. How many rows of five are there in
20? There are four rows of five. 20 divided by five is four. We used the array to help us find
Count back to find the missing
number. 25 divided by five equals what.
In this question, we have to divide
25 by five. In other words, we have to work out
how many fives there are in the number 25. And we’ve been given this number
line to help. We can see the number line starts
at zero and ends at 25. And we’re told we have to count
back to find the missing number. We need to count back in fives to
find out how many fives there are in 25. We need to start at 25 and count
back in fives until we reach zero. Five less than 25 is 20. Five less than 20 is 15. 25, 20, 15, 10, five, zero.
How many times did we count back in
fives? Five times. Now we know there are five fives in
25. 25 divided by five equals five. We counted back in fives from 25 to
find the answer.
Complete the following table.
In this question, we have to
complete the missing number from the table. This is a division table. We take the number at the top — in
this case it’s 20 — divide it by five, and write the answer below. 20 divided by five is four. 25 divided by five is five. 30 divided by five is six. What is 40 divided by five? Let’s use our knowledge of the five
times table to help. Five multiplied by what equals
40. One times five is five. Two fives are 10. Three fives are 15. Four fives are 20. Five fives are 25. Six times five is 30. Seven times five is 35. Eight times five is 40. If we know that eight times five is
40, then 40 divided by five is eight.
We completed the table with the
missing number which is eight, because 40 divided by five is eight.
What have we learned in this
video? We’ve learned how to divide by five
using arrays, number lines, and the five times table.