Tính nhanh: a, 40.113.25 – 20.112.50 b, 27 + 27.5 + 27.7 – 27.2
Giải thích
a) 40.113.25 – 20.112.50 = 40.25.113 – 20.50.112
= 1000.113 – 1000.112 = 1000(113 – 112) = 1000.1 = 1000
b) 27 + 27.5 + 27.7 – 27.2 = 27.(1 + 5 + 7 – 2) = 27.11 = 297
c) 754.75 – 25.2262 + 4568 = 754.75 – 25.3.754 + 4568
= 754.75 – 75.754 +4568 = 754.(75 – 75) + 4568 = 4568