急問數學高手請進來20分

1.27+0.76+3.77-2.54+4.25-0.57的估算 = 1.3+0.8+3.8-2.5+4.3-0.6 = 6.8
0.33除以120乘99的估算 = 0.3/120x100 =30/120 =1/4 = 0.25
3488乘8除7的估算 = 3500x8/7 =28000/7 =4000
己知$11可買橙6個使用相容數字估算16個橙的售價 = 11/6x16 =2x16=32

希望幫到你:)

1.27 + 0.76 + 3.77 - 2.54 + 4.25 - 0.57
≒ 1+1+3-3+1-1
= 2

0.33 ÷ 120 x 99
= 0.1 x 33 ÷ 120 x 99
= 0.1 x 3 x 11 ÷ 3 x 99
= 0.1 x 99 x 11
≒ 0.1 x 100 x 10
= 100

3488 x 8 ÷ 7
≒ 3500 ÷ 7 x 8
= 500 x 8
= 4000

16個橙的售價
= 16 x ($11 ÷ 6)
≒ 16 x ($12 ÷ 6)
= 16 x $2
= $32