- operations and brakets

operations and brackets 

       reminder

1)                            9,514 -  1,6                                                              

►       answer                                                          

 

 

 

                             

                               2)                    4,56 x 1,7                                                                                             

                                                     ►         answer      

                                                                                                                      

  exercise                                                               

                reckon

3,07 + 11,354 + 0,009

►         answer                              

 

operatins with brackets

,  rule1

when there are brackets , operations inside brackets must be done first

  example 1

11-(15-8) = 11 - 7         

=  4                      

  example 2

4,25 x [ 17 -( 5+3) x2 ] = 4,25 x [ 17 -8 x2 ]                     

=4,25 x [ 17 -16 ]                                

  = 4,25 x  1                                  

= 4,25                                         

 

operatins without brackets

 rule 2

when  there's no bracket between operations , multiplications and divisions must be done first , then addition and subtractions

example 3

4 + 2×3 = 4 + (2×3) = 4 + 6 = 10

Distributive property

( m + n ) · k = m ·  k + n · k

 ►       exercises 

rules

a - ( b + c ) = a - b - c

a - ( b - c ) = a - b + c

 a + ( b + c ) = a + b + c

a + ( b - c ) = a + b - c

( a + b ) ( c - d ) = ac - ad + bc - bd

( a - b ) ( c + d ) = ac + ad - bc - bd

( a + b ) ( c + d ) = ac + ad + bc + bd

( a- b ) ( c-  d ) = ac - ad - bc + bd

►            exercises