2.
口算。
(1)360÷9=
(2)64×2= | (3)375+210= (4)2700÷3= | (5)800÷8= | (6)100-47= (7)2.4+1.6= | (8)2.5+3.6= | (9)544÷9≈ (10)3-0.9= | (11)1.1-0.9= | (12)69×3≈
| (2)33.2-13.4-12.6 =33.2-(□○□) =□ (3)38×12 =38×□+38×□ =□ | (4)56×39 =56×□-56×□ =□(5)346-100+99-98+97-96+95-94+…+5-4+3-2+1 =346-□×□ =346-□ =□
| (2)(367-288)×27 | (3) l154-298+314 (4)810÷9×35 | (5)40×25-286 | (6)54×(116 - 29)
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