One Less: Numbers up to 10
In this video, we will learn how to
find one less the numbers up to 10 by taking away one object from a group and
counting the number that remains. Let’s use this counting frame to
help us. What does one less mean? To find one less than a number, we
need to count back. Nine is one less than 10. Eight is one less than nine. Seven is one less than eight. Six is one less than seven. Five is one less than six. Four is one less than five. Three is one less than four. Two is one less than three. And one is one less than two. So to find one less than six, we
would need to count back one from six. One less than six is five.
Here’s another way to find one less
than a number. We have 10 cubes in our counting
frame. To find one less, we could just
take one cube away. Can you see how many cubes are
left? There are nine. So we can say that one less than 10
We’ve learned two different ways to
find one less than a number. We could use objects and then take
away one, or we could count back one. Let’s try some questions now to
help us practice what we’ve learned.
Complete: What is one less than
In this question, we’re shown a
group of jelly beans. We don’t need to count the jelly
beans because we’re already told that there are four. We have to find one less than
four. There’s a big hint in the
picture. The arrow is showing us to take one
jelly bean away. Finding one less is the same as
taking away one. So let’s take away one jelly
bean. How many are left? There’s one, two, three. Four take away one is three. One less than four is three. Three is one less than four.
What number is one less than
five? Hint: Take away one block.
In this question, we have to find
one less than five. And we’re given a picture of a cube
train with five blocks. We’re also given a hint. We’re told to take away one
block. Taking away one is the same as
finding one less. So let’s take away one block. How many are left? One, two, three, four. One less than five is four. We had five blocks to start with,
and we took away one because taking away one is the same as finding one less. One less than five is four.
Which set of blocks shows one less
In this question, we’re shown four
different cube trains, each containing a different number of blocks. We have to find the cube train that
has one less than six. What is one less than six? We could use this counting frame to
help us. We need to find one less than
six. So we need to place six blocks in
our counting frame. To find one less, we need to take
one block away. One less than six is five.
Now what we need to do is select
the cube train which has five blocks because five is one less than six. Let’s count the number of blocks in
the first cube train. One, two, three, four, five. This is the set of blocks we’re
looking for. Five is one less than six. This cube train has six blocks,
this one has seven, and this one has four. The set of blocks which shows one
five [six] is the one with five blocks.
There are seven squares. Pick the line that has one less
square. Is it the line with six squares,
five squares, or eight squares?
We’re shown seven squares, and we
have to pick the line of squares which has one less than seven. To find one less than seven, we
could just take away one square. How many squares do we have
now? One, two, three, four, five,
six. One less than seven is six. Which of our lines of squares has
six squares? It’s this one. One less than seven is six.
What have we learned in this
video? We have learned how to find one
less than a number by taking away one or counting back one from an amount.