16×40÷2.5×40=6.4
1125-997= 1125-(997+3)+3=128
998+1246+9989=(998+2+1246-13+9989+11)=12233
16÷2.5=(16×4)÷(2.5×4)=64÷10=6.4
1125-997=1125-1000+3=128
998+1246+9989=1000+1246+10000-2-11=12233
16÷2.5
=(16×4)÷(2.5×4)
=64÷10
=6.4
1125-997
=1125-1000+3
=125+3
=128
998+1246+9989
=(998+2)+(1246-2-11)+(9989+11)
=1000+1233+10000
=12233