Question

小学四年级巧算（脱式计算）

1. 66×21+19×21+85×19
2. 36×111+888×8

Answer 1

（1）66x21+19x21+85x19
=（66+19）x21+85x19
=85x21+85x19
=85x（21+19）
=85x40
=3400
（2）36x111+888x8
=36x111+111x8x8
=36x111+111x64
=（36+64）x111
=100x111
=11100

Answer 2

1.66*21+19*21+85*19
=（66+19）*21+85*19
=85*21+85*19
=85*（21+19）
=85*40
=3400
2.36*111+888*8
=36*111+111*8*8
=36*111+111*64
=（36+64）*111
=100*111
=11100

Answer 3

1、66×21+19×21+85×19=(66+19)×21+85×19=85×21+85×19=85×(21+19)=85×40=3400
2. 36×111+888×8=36×111+111×8×8=36×111+111×64=(36+64)×111=100×111=11100