PHYZR #3: Doing Math with Tens Prelims – Page 4

We only have ten symbols to represent an infinite amount of numbers. 5 7 2 8 9 6 3 1 4

1 7 8 9 6 5 2 1 3 4 Problem: How do we write numbers larger than nine? 2 1 3 4 “tens” “ones” Solution: add a new number place!

2. IN BETWEEN NUMBERS Problem: How do we write numbers in between other numbers? 1 2 3 2 1 . 4 1 3 5 2 what number is this? “ones” “tenths” Solution: add a decimal place!

Why does this work? Every ten symbols, we have to move to a new place! 3. MULTIPLYING BY TEN   , . Get bigger by ten times (one place) Why does this work? Every ten symbols, we have to move to a new place!    

Get smaller by ten times (one place) 4. DIVIDING BY TEN   , . Get smaller by ten times (one place)    

Get bigger by ten times (one place) 3. MULTIPLYING BY TEN   , . Get bigger by ten times (one place)    

Get smaller by ten times (one place) 4. DIVIDING BY TEN   , . Get smaller by ten times (one place)      

Multiply by ten makes the number ______. 5. RULE SUMMARY Multiply by ten makes the number ______. Divide by ten makes the number ______. bigger smaller , . multiply divide (bigger) (smaller)

6. PRACTICE , . Solve each problem:   50   0.2 4 0.07 3.6 150 0.4 0.04

We’ll come back to this after we finish Page #3

7. POSITIVE EXPONENTS   , . Move 3 spaces bigger.        

8. NEGATIVE EXPONENTS   , . Move 3 spaces smaller.        

9. PRACTICE , . Solve each problem:   700   0.02 200 0.0001 0.007 8200

Which number is the largest? 10. WEIRD LOOKING NUMBERS Which number is the largest? .   5 =   . 5 = .   =   5 = 5 .   =   5 . = 5 .