1.125x3+125x5
=125x(3+5)
=125x8
=1000;
2.25x(4+8)
=25x4+25x8
=100+200
=300;
3.10-3-7
=10-(3+7)
=10-10
=0
4.20÷4÷5
=20÷(4x5)
=20÷20
=1;
5.3+4+7+6
=(3+7)+(4+6)
=10+10
=20;
6.8+1+9
=8+(1+9)
=8+10
=18;
1.125x3+125x5
=125x(3+5)
=125x8
=1000;
2.25x(4+8)
=25x4+25x8
=100+200
=300;
3.10-3-7
=10-(3+7)
=10-10
=0
4.20÷4÷5
=20÷(4x5)
=20÷20
=1;
5.3+4+7+6
=(3+7)+(4+6)
=10+10
=20;
6.8+1+9
=8+(1+9)
=8+10
=18;