### Video Transcript

Counting in 50s

In this video, we’re going to learn
how to count objects in groups of 50 and how to count in 50s to 1000. These children are practicing
counting in 50s. 50, 100, 150, 200, 250, 300, 350,
400, 450, 500. Why not count along? 550, 600, 650, 700, 750, 800, 850,
900, 950, 1000. They counted in 50s up to 1000. Did you notice any patterns in the
numbers as the children were counting in 50s? There’s a hundreds number, a number
ending in two zeros, followed by a number ending in 50. This pattern repeats. 900 is a hundreds number ending in
two zeros. It’s followed by a number ending in
50. This pattern continues if we count
in 50s all the way up to 1000. We have a hundreds number, followed
by a number ending in 50.

We can model the number 50 using
five tens. If we put two 50s together, we get
100. Double 50 or 50 times two is
100. Two 50s equal 100. Watch how the numbers increase as
we count in 50s. 50, 100, 150, 200, 250, 300. As we count forward, the numbers
increase by 50, and if we count back, the numbers decrease by 50. Let’s try some questions where we
need to practice counting in 50s.

There are 50 coins in each jar. How many coins are there in
total? Hint: Count in 50s.

In this question, we’re told that
we have to count in 50s to find the total number of coins. This is because there are 50 coins
in each jar. Let’s count how many jars there
are. One, two, three, four, five, six,
seven, eight, nine. If there are nine jars, each
containing 50 coins, then we could count in 50s nine times. Let’s use our number line to
help. 50, 100, 150, 200, 250, 300, 350,
400, 450. We knew there were 50 coins in each
jar. And we counted the number of jars
and found that there were nine. We started at 50 and counted
forward in 50s. The total number of coins is
450.

The students are counting in
50s. 50, 100, what, 200, 250, what. What number did Amelia say? What number should Ethan say?

In this question, the children are
counting in 50s. We need to count in 50s to find the
number that Amelia said and the number that Ethan should say because these two
numbers are missing. Let’s start at the beginning. The first number is 50. 50 more than 50 is 100. We know that double 50 is 100. So two 50s make 100. To find Amelia’s number, we need to
add 50 to 100. 50, 100, 150. The number Amelia said is 150. 50 more than 150 is 200. 50 more than 200 is 250. What is 50 more than 250? It’s 300. The students were counting in
50s. 50, 100, 150, 200, 250, 300. The number Amelia said is 150, and
the number Ethan should say is 300. We counted forward in 50s to find
the missing numbers.

Find the missing number on the
given number line.

We’re given a number line, and we
have to find the missing number. The number line starts at zero and
ends at 1000. If we start at zero and count
forward, we can see the numbers are increasing by 50 each time. And we can see from the green
arrows that if we count back, the numbers are decreasing by 50 each time. These green arrows are a hint. They’re telling us that we need to
count back in 50s to find the missing number. If we count back from 750, we get
to 700. 650, 600. We’re taking away 50 each time. So what is 50 less than 600? 550, 500, and the next number is
the missing number. What number is 50 less than 500 and
50 more than 400? It’s 450. To find the missing number, we
counted back in 50s. 50 less than 500 is 450. We found the missing number using
the number line.

Daniel made trays of five
cookies. Count in fives to find how many
cookies he made. Five, 10, what, what, what. Hannah bought boxes of 50
cookies. 50, 100, what, what, what. Count in 50s to find how many
cookies she bought.

This is a two-part question. In the first part of the question,
we have to count in fives to find the number of cookies Daniel made. And in the second part of the
question, we have to count in 50s to find out how many cookies Hannah bought. Let’s start by counting in
fives. Five, 10, 15, 20, 25. We know that Daniel baked 25
cookies. We counted in fives because Daniel
baked trays of five cookies. Five, 10, 15, 20, 25.

Now we need to count how many
cookies Hannah bought. Her boxes contain 50 cookies, so we
need to count in 50s. We could count in fives to
help. Daniel starts with five cookies,
which is the same as five ones. And Hannah starts with 50 cookies,
which is the same as five tens. Five ones, five tens. 10 ones and 100 is 10 tens. Five, 10, 15, 50, 100. What number comes next? What number is 15 tens? It’s the number 150. The next number in Daniel’s
sequence is 20: 20 ones. So the next number in Hannah’s
sequence is 20 tens, which is 200. The final number in Daniel’s
sequence is 25.

Which number is 10 times greater
than 25? It’s 250. 50, 100, 150, 200, 250. Hannah bought 250 cookies. Daniel made trays of five cookies,
so we counted in fives to find out how many cookies he made. Five, 10, 15, 20, 25. Hannah bought boxes of 50
cookies. We counted in 50s to find out how
many cookies she bought. 50, 100, 150, 200, 250. Counting in fives can help us to
count in 50s. When we count in 50s, the numbers
are 10 times greater than when count in fives. Daniel baked 25 cookies and Hannah
bought 250 cookies.

What have we learned in this
video? We have learned how to count in 50s
up to 1000. And we’ve also learned that we can
count in fives to help us count in 50s because 50 is 10 times greater than five.