Unit 3 Let’s do math! LESSON 17 课件 (共15张PPT)

课件15张PPT。UNIT 3 LET’S DO MATHLESSON 1720~90的十位数的整数均以后缀-ty结尾
20 twenty 30 thirty
40 forty 50 fifty
60 sixty 70 seventy
80 eighty 90 ninety
Again2030405060twentythirtyfortyfiftysixty708090100seventyeightyninetyone hundredLet’s do itThere are forty bananas.My brother took away ten.How many bananas are left?40-10=30
Forty minus ten is thirty.
Thirty bananas are left.
There are fifty apples.My sister took away twenty.How many apples are left?50-20=30
Fifty minus twenty is thirty.
Thirty apples are left.
There are fifty eggs.My mother took away thirty.How many eggs are left?50-30=20
Fifty minus thirty is twenty.
Twenty eggs are left.
There are sixty pears.My father took away ten.How many pears are left?60-10=50
Sixty minus ten is fifty.
Fifty pears are left.
Practice1. 90-20=?2. 80-20=?Ninety minus twenty is________.Eighty minus twenty is________.One hundred minus twenty is________.3. 100-20=?seventysixtyeightyFifty minus thirty is________.Sixty minus thirty is________.Ninety minus forty is________.4. 50-30=?5. 60-30=?6. 90-40=?twentythirtyfiftyHomework: 回家把今天学到的数字
数给爸爸妈妈听。