内容正文:
Unit 6 I have fifty markers.
北京版三年级上册
Lesson 21
You have so many collections. We need to learn something about addition and subtraction. Then you can collect more and more.
My collections
What are they talking about?
Look and think
Let’s watch
Listen and complete
It’s easy. Fifty ____ten is sixty.
So the missing numbers are
_______and ___________.
plus
Look at the numbers on the ____________:
50, 60, ____, ____, 90. Who can guess
the missing numbers?
blackboard
seventy
eighty
Let’s learn
Look at the numbers on the blackboard:
blackboard
Let’s learn
So the missing numbers are seventy and eighty.
70
seventy
Let’s learn
Fifty plus ten is sixty.
+
plus
Let’s learn
So the missing numbers are seventy and eighty.
80
eighty
Listen and complete
Ninety minus
ten is ______.
eighty
____________minus
ten is ___________.
One hundred
ninety
Let’s learn
One hundred minus ten is ninety.
100
one hundred
Let’s learn
One hundred minus ten is ninety.
-
minus
Let’s learn
One hundred minus ten is ninety.
90
ninety
Listen and complete
_________!
Well done
So the missing numbers
are eighty and seventy.
What does Lala ask?
Who can guess the missing numbers?
Listen and answer
What are the missing numbers?
Seventy and eighty.
Listen and answer
Listen and repeat
Look at the numbers on the blackboard:
50, 60, ____, ____, 90. Who can guess
the missing numbers?
Listen and repeat
It’s easy. Fifty plus ten is sixty.
So the missing numbers are
seventy and eighty.
Listen and repeat
One hundred minus
ten is ninety.
Listen and repeat
Ninety minus
ten is eighty.
Listen and repeat
So the missing numbers
are eighty and seventy.
Listen and repeat
Well done!
Let’s role-play
Lala: Look at the numbers on the blackboard: 50, 60, ____, ____, 90. Who can guess the missing numbers?
Baobao: It’s easy. Fifty plus ten is sixty. So the missing numbers are seventy and eighty.
Let’s role-play
Baobao: One hundred minus ten is ninety.
Boy: Ninety minus ten is eighty.
Lingling: So the missing numbers are