题目
下面各题,能简便计算的用简便方法计算。
① × ×
② × ×16
③ + + +
④5.2×3.6+3.6×4.8
⑤ × 7×12×
⑥ × ×
答案:① 35 × 25 × 38 = 625× 38 =9100 ② 54 × 18 ×16 =532×16 =52 ③ 29 + 613 + 79 + 713 =29+79+(613+713) =1+1 =2 ④ 5.2×3.6+3.6×4.8 =(5.2+4.8)×3.6 =10×3.6 =36 ⑤ 74 × 7×12× 821 = 74×12×(821× 7) =21×83 =56 ⑥ 251 × 3435 × 713 =23×235×713 =23×25×113 =4195