Video Transcript
Counting Forward and Backward
within 100
In this video, we will learn how to
count within 100 in ones from any starting number and complete the missing numbers
in a counting sequence.
When we’re counting within 100, it
really helps to use 100 square. We can use 100 square for lots of
things in maths. In this video, we’re going to use
it to help us count forward or backward from a given number and to complete
sequences of numbers with missing numbers.
How do we find numbers on 100
square? How would we find the number
87? There are lots of ways. 87 is a two-digit number. And we know it has eight tens. Here’s the number 80. We could count forward from 80
until we reach 87. 80, 81, 82, 83, 84, 85, 86, 87.
We could also use the seven digit
to help us find the number 87 in the 100 square. The seven is worth seven ones. All of the numbers in this column
have seven ones. We could start at seven and count
down until we reach 87. 7, 17, 27, 37, 47, 57, 67, 77,
87.
We can also use 100 square to find
the number that comes before a given number and the number that comes after. This time, the number we’re given
is 55. And we’ve placed a counter on the
number 55 on the 100 square. What number comes before 55? It’s 54. The number which comes after 55 is
56. Let’s try some example questions
now to help us practice counting forward and backward within 100 using our 100
square.
Which number comes just before
96?
Let’s use our 100 square to
help. Let’s find the number 96. The number 96 is very close to
100. We could count backward until we
reach 96. 100, 99, 98, 97, 96. We’ve placed a counter on number
96. Which number comes before 96? It’s number 95. We used 100 square to help us find
the number 96. We counted backward to find the
number that comes before. The number just before 96 is
95.
Complete the following pattern: 49,
50, 51, what, what.
We’re shown a sequence of numbers
which begins with number 49. The next number is 50, and then
51. The next two numbers are
missing. Let’s use our 100 square. We need to start counting at number
49 and count forward until we reach our missing numbers, 49, 50, 51. The number which comes next is
number 52. And if we count forward one more
time, we can see that the number which comes after number 52 is number 53.
We completed the pattern using the
numbers 52 and 53. We used our 100 square to help us
count forward. 49, 50, 51, 52, 53. The missing numbers are 52 and
53.
Start at 46. Count on eight more.
In this question, we have to use
the hundreds chart to help us find the number which is eight more than 46. So, we need to start at 46 and
count forward eight more. One, two, three, four, five, six,
seven, eight. Eight more than 46 is 54.
We used our hundreds chart. And we started counting at number
46. And we counted forward eight
more. Eight more than 46 is 54.
What have we learned in this
video? We’ve learned how to count forwards
and backwards within 100 using 100 square. We’ve also learned how to find the
number before or after a given number and how to complete the missing numbers in a
count sequence.
