怎样算简便就怎样算.(1)12.74-18+2.26-9.875(2)4.8×3.9+6.1×445(3)(2.5-3.2×516)÷(4815÷3.4)(4)18÷[56+(58-13)].-六年级数学
题文
怎样算简便就怎样算. (1)12.74-
(2)4.8×3.9+6.1×4
(3)(2.5-3.2×
(4)18÷[
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答案
(1)12.74-
=12.74-0.125+2.26-9.875, =(12.74+2.26)-(0.125+9.875), =15-10, =5; (2)4.8×3.9+6.1×4
=4.8×3.9+6.1×4.8, =4.8×(3.9+6.1), =4.8×10, =48; (3)(2.5-3.2×
=(2.5-1)÷(
=1.5÷
=
=
(4)18÷[
=18÷[
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