Question

[★长ØØ★_๛๖ۣۜKĭм ๖ۣۜHεℓℓ ๖ۣۜKĭツ]

Giúp mk nha mk tick cho :)

Bài 1 : Tính nhanh ( nếu có thể )

a, ( 1+ 2+3+4+......+100) . ( 1 + 4 + 9 +.....+100) : ( 65 . 111 -13 .15 .37 )

b, 19991999 . 1998 - 19981998 . 1999

c, 1990 . 1990 - 1992 . 1988

d, ( 1374 . 57 + 687 . 86 ) : ( 26 . 13 + 74 . 14 )

e, ( 124 . 237 + 152 ) : ( 870 + 235 . 122 )

GIÚP MK NHA RỒI MK TICK CHO !

Answer 1

[Diệu Anh]

a) ( 1+ 2+3+4+......+100) . ( 1 + 4 + 9 +.....+100) : ( 65 . 111 -13 .15 .37 )

= ( 1+ 2+3+4+......+100) . ( 1 + 4 + 9 +.....+100) : ( 13.5 . 3.37 - 13.15.37)

= ( 1+ 2+3+4+......+100) . ( 1 + 4 + 9 +.....+100) : ( 13.15.37 - 13.15.37)

= ( 1+ 2+3+4+......+100) . ( 1 + 4 + 9 +.....+100) : 0

Sai đề r bn ơi :((

Answer 2

[Diệu Anh]

b) 19991999 . 1998 - 19981998 . 1999

= ( 19981998 + 10001) .1998 - 19981998 . ( 1998+1)

= 19981998 .1998 + 10001 .1998 - 19981998 .1998 + 19981998

= 0