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.