Question

[Hoàng Thùy Linh]

Tính nhẩm :

1. ( 1999 + 313 ) – 1999 ; ( 1435 + 213 ) -13
2. 2034 – ( 34 + 1560 ) ; 1972 – ( 368 + 972 )
3. 364 – ( 364 – 111 ) ; 249 – ( 75 – 51 )

Answer 1

[ミ★๖ۣۜSóĭ๖Dạo๖ۣۜBước★彡]

Giải :

1. ( 1999 + 313 ) – 1999 = 1999 – 1999 + 313 = 313

( 1435 + 213 ) – 13 = 1435 + ( 213 – 13 ) = 1435 + 200 = 1635

2. 2034 – ( 34 + 1560 ) = ( 2034 – 34 ) – 1560 = 2000 – 1560 = 440

1972 – ( 364 + 972 ) = 1972 – 972 – 368 = 1000 – 368 = 632

      c.    364 – ( 364 – 111 ) = 364 – 364 + 111 = 111

             249 – ( 75-51 ) = ( 249 + 51 ) – 75 = 300 – 75 = 225