1. 135²-35²=(135-35)(135+35)=100×170=17000
2. 17,5²-9,5² = (17,5-9,5)(17,5+9,5) = 8×27 = 1×1 = 1
131,5²-3,5² (131,5-3,5)(131,5+3,5) 128×135 16×5 80
3. 52²-37²+39²-36² =(52-37)(52+37)+(39-36)(39+36)=15×89+3×75= 4
57²-32² 45²-30² (57-32)(57+32) (45-30)(45+30) 25×89 15×75 5
4. 41²-17²-39²-17²=(41-17)(41+17) - (39-17)(31+17) =24×58-22×48=58 -2=140
37²-31² 45²-21² (37-31)(37+31) (45-21)(45+21) 6×68 24×66 17 3 51