Move the decimal point

37.2 0.372 3.72 372 Observe the numbers above， 37.2 0.372 3.72 372 Observe the numbers above， what’s the same,what’s the different？ Can you put in order of size from biggest to smallest?

What does each number mean in its place? 25.763 1.023 0.505

372 37.2 3.72 0.372 What is the relationship among them?

10×0.001=0.01

10×0.01=0.1

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 10×0.1=1

Observe the position of the decimal point in three multiplication equation, what can you find? 0.001×10=0.01 0.01×10=0.1 0.1×10=1 When you multiply by 10, you move the decimal point one place to the right .

When we know the multiplication fact ,can you find the related division facts? 0.001×10=0.01 0.01×10=0.1 0.1×10=1 0.01÷10=0.001 0.1÷10=0.01 1÷10=0.1 Observe the position of the decimal point in three division equations, what can you find?

Observe the position of the decimal point in three division equations, what can you find? 0.01÷10=0.001 0.1÷10=0.01 1÷10=0.1 When you divide by 10, you move the decimal point one place to the left . .

Have a try 14.1 Omit the decimal point 141 Add a zero 1410 1.41×10= 1.41×100= 1.41×1000= 14.1 move the decimal point one place to the right move the decimal point two places to the right move the decimal point three places to the right Omit the decimal point 141 Add a zero 1410

Exercise 93.07×10= 93.07×100= 93.07×1000= 93.07×10000= 930.7 9307 93070 930700

If there is no digit in front of the decimal point,add 0. Division facts 1.41 ÷10 = 1.41 ÷100= 1.41÷1000= 0.141 move the decimal point one place to the left move the decimal point two places to the left move the decimal point three places to the left 0.0141 0.00141 If there is no digit in front of the decimal point,add 0.

Exercise 93.07÷10= 93.07÷100= 93.07÷1000= 93.07÷10000= 9. 307 0.9307 0.09307 0.009307

Do the following calculations 4.23×10 0.63×10 0.427×100 1000×0.64 141.2÷100 19.3÷10 47÷100 16÷1000 =42.3 =1.412 =6.3 =1.93 =42.7 =0.47 =640 =0.016

Copy and complete 0.45×（ ）=4.5 43÷（ ）=0.43 10 100 0.45×（ ）=45 0.45×（ ）=4.5 0.45×（ ）=45 0.45×（ ）=4500 43÷（ ）=0.43 43÷（ ）=0.043 430÷（ ）=0.43 10 100 100 1000 10000 1000

Fill in ○ with ×、÷ Fill in（ ）with number 3.8○10=38 47○100=0.47 3.8○10=38 47○100=0.47 0.0081 ○100=0.81 17.5○10=1.75 62.7○1000=0.0627 0.084 ○100=8.4 5.27 ○( )=527 3218○( ) =3.218

Fill in ○ with ×、÷ Fill in（ ）with number 3.8○10=38 47○100=0.47 3.8○10=38 47○100=0.47 0.0081 ○100=0.81 17.5○10=1.75 62.7○1000=0.0627 0.084 ○100=8.4 5.27 ○( )=527 3218○( ) =3.218 × ÷ × ÷ ÷ × 100 1000 × ÷

3.72 ×23=A 37.2 ×23=B 372 ×23=C What is the relationship among A,B,C?

Thank you!