✨ 最佳解答 ✨
7)X²-Y²=(X+Y)(X-Y)
(1/120)(360²-120²)
=(1/120)(360+120)(360-120)
=(1/120)*480*240
=960
8)先化簡,不用把答案計算出來
A:(345+45)(345-45)=390*300
B:(451+151)(451-151)=602*300
C:(532+232)(532-232)=764*300
D:(425+175)(425-175)=(300*2)*250
9)
133÷135約等於0.99
★算到小數點後第二位就好,第三位四
捨五入
133×0.99
=133(1-0.01)
=133-1.33
=131.67