Index:  
Unit plans  . 
*Adding and Subtracting 

Multiplying and dividing 

Basic Operations  Basic Operations Cards 
add  subtract 

easier... 51 + 23= 50 + 1 + 20 + 3 
(can be tricky if unit to be subtracted is larger) easier ... 54  12= (50  10 = 40) (4  2 = 2) 40 + 2 = harder ... 54  16 = (40  10 = 30) (14  6 = 8) 30 + 8 = 
add  subtract 

easier .... 55 + 23= 55 + 20 = 75 75 + 3 = 
(no difference if unit being subtracted is larger) smaller unit being subtracted ... 55  23 = 55  20 = 35 35  3 = larger unit being sutbtracted ... 55  26= 55  20 = 35 35  6 = 
addition  subtraction 

29 + 13= 30 + 10 + 3= 43 43  1 = 
(can be tricky especially if the unit being subtracted is larger) easier .... 57  25= (50  20 = 30) (7  5 = 2) 30 + 2 = harder ... 57  28 = (40  20 = 20) (17  8 = 9) 20 + 9 = 
addition  subtraction 

28 + 14 = 28 + 10 + 4 
(size of the units makes no difference ... a real bonus esp for LA children) smaller unit .... 28  14 = 28  10 = 18 28  4 = larger unit ... 28  19 = 28  10 = 18 18  9 = 
addition  subtraction 

easier ... 27 + 29 = 25 + 2 + 25 + 4 
harder ... (double is less apparent) 53  26 = 50 25 =25 (3  1 = 2) 25 + 2 = 
addition  subtraction 

easier .... 14 + 7 = 21 harder ... 15 + 9 = (14 + 7 = 21) (1 + 2 = 3) 21 + 3 = 
easier ... 28  7 = 21 hard  can children cope with inverting? ... 27  9 = (28  7 = 21) (+1 + 2 = +3) 21  3 = 18 