Question

[Trần Thảo Nhi]

Tính nhanh

a)        1000-3999+400-4999+5000-5999+6000-6999-700

b)        3128-725-275

Answer 1

[nguyễn phương linh]

a, 1000-3999+400-4999+5000-5999+6000-6999-700

=(1000+5000+6000)+(-3999-4999-5999-6999)+(400-700)

=12000-13998-300

b,3128-725-275

=3128-(725-275)

=3128-450

=2678