5392+3997
=5392+4000-3
=9392-3
=9389
7362-2999
=7362-3000+1
=4363
62.4÷2.5÷4
=62.4÷(2.5x4)
=6.24
125÷(50÷8)
=125x8÷50
=20
55x0.99
=55x(1-0.01)
=55-0.55
=54.45
7.2x10.1
=7.2x(10+0.1)
=7.2x10+7.2x0.1
72.72
8÷125
=(8x8)÷(125x8)
=0.064