a ) 42.13 + 22.15 - 42.3 - 22.5
= 42 . 13 - 42.3 + ( 22.15 - 22. 5 )
= 42 . ( 13 - 3 ) + 22. ( 15 - 5 )
= 42. 10 + 22 . 10
= 10. ( 42 + 22 )
= 10 . 64
= 6400
b ) 24 . 42 - 35. 24 - 24.7
= 24. ( 42 - 35 - 7 )
= 24 . 0
= 0
\(a,42.13+22.15-42.3-22.5\)
\(=42.13-42.3+22.15-22.5\)
\(=42.\left(13-3\right)+22.\left(15-5\right)\)
\(=42.10+22.10\)
\(=10.\left(22.42\right)\)
\(=10.64=640\)
\(b,24.42-35.24-24.7\)
\(=24.\left(42-35-7\right)\)
\(=24.0=0\)
Câu a tui ghi nhầm :
10.64 = 640 chứ không phải 6400
a/ 42.13 + 22.15 - 42.3 - 22.5
= 42 . 13 - 42 . 3 + 22 . 15 - 22. 5
= 42 ( 13 - 3 ) + 22 ( 15 - 5 )
= 42 . 10 + 22 . 10
= 10 ( 42 + 22 )
= 10 . 64 = 6400
b/ 24.42 - 35.24 - 24.7
= 24 ( 42 - 35 - 7 )
= 24 . 0 = 0
mk ik
a ) 42.13 + 22.15 - 42.3 - 22.5
= 42 . 13 - 42.3 + ( 22.15 - 22. 5 )
= 42 . ( 13 - 3 ) + 22. ( 15 - 5 )
= 42. 10 + 22 . 10
= 10. ( 42 + 22 )
= 10 . 64
= 6400
b ) 24 . 42 - 35. 24 - 24.7
= 24. ( 42 - 35 - 7 )
= 24 . 0
= 0
#LYB#
