$30 × 3 =$ $2 × 3 =$ $32 × 3 =$
$40 × 2 =$ $3 × 2 =$ $43 × 2 =$
$10 × 5 =$ $7 × 5 =$ $17 × 5 =$
$2 2 × 4 =$ $3 1 × 3 =$
$40 × 2 =$ $3 × 2 =$ $43 × 2 =$
$10 × 5 =$ $7 × 5 =$ $17 × 5 =$
$2 2 × 4 =$ $3 1 × 3 =$
答案
$90$;$6$;$96$;$80$;$6$;$86$;$50$;$35$;$85$;$88$;$93$。
解析
$30×3$:把30看作3个十,3个十乘3是9个十,即$90$;
$2×3 = 6$;
$32×3$:先算$30×3 = 90$,再算$2×3 = 6$,最后将两结果相加,$90 + 6 = 96$;
$40×2$:把40看作4个十,4个十乘2是8个十,即$80$;
$3×2 = 6$;
$43×2$:先算$40×2 = 80$,再算$3×2 = 6$,最后相加$80+6 = 86$;
$10×5$:把10看作1个十,1个十乘5是5个十,即$50$;
$7×5 = 35$;
$17×5$:先算$10×5 = 50$,再算$7×5 = 35$,最后相加$50 + 35=85$;
$22×4$:先算$20×4 = 80$,再算$2×4 = 8$,最后相加$80+8 = 88$;
$31×3$:先算$30×3 = 90$,再算$1×3 = 3$,最后相加$90 + 3=93$。
$2×3 = 6$;
$32×3$:先算$30×3 = 90$,再算$2×3 = 6$,最后将两结果相加,$90 + 6 = 96$;
$40×2$:把40看作4个十,4个十乘2是8个十,即$80$;
$3×2 = 6$;
$43×2$:先算$40×2 = 80$,再算$3×2 = 6$,最后相加$80+6 = 86$;
$10×5$:把10看作1个十,1个十乘5是5个十,即$50$;
$7×5 = 35$;
$17×5$:先算$10×5 = 50$,再算$7×5 = 35$,最后相加$50 + 35=85$;
$22×4$:先算$20×4 = 80$,再算$2×4 = 8$,最后相加$80+8 = 88$;
$31×3$:先算$30×3 = 90$,再算$1×3 = 3$,最后相加$90 + 3=93$。
$12 × 2 =$ $28 × 2 =$ $28 × 3 =$
$15 × 3 =$ $23 × 4 =$ $37 × 2 =$
$41 × 9 =$ $16 × 5 =$ $15 × 6 =$
$15 × 3 =$ $23 × 4 =$ $37 × 2 =$
$41 × 9 =$ $16 × 5 =$ $15 × 6 =$
答案
24,56,84,45,92,74,369,80,90
解析
12×2:10×2=20,2×2=4,20+4=24
28×2:20×2=40,8×2=16,40+16=56
28×3:20×3=60,8×3=24,60+24=84
15×3:10×3=30,5×3=15,30+15=45
23×4:20×4=80,3×4=12,80+12=92
37×2:30×2=60,7×2=14,60+14=74
41×9:40×9=360,1×9=9,360+9=369
16×5:10×5=50,6×5=30,50+30=80
15×6:10×6=60,5×6=30,60+30=90
28×2:20×2=40,8×2=16,40+16=56
28×3:20×3=60,8×3=24,60+24=84
15×3:10×3=30,5×3=15,30+15=45
23×4:20×4=80,3×4=12,80+12=92
37×2:30×2=60,7×2=14,60+14=74
41×9:40×9=360,1×9=9,360+9=369
16×5:10×5=50,6×5=30,50+30=80
15×6:10×6=60,5×6=30,60+30=90
(1)
①3 箱可乐共有多少瓶?
②买 2 箱可乐要多少元?
(2) 张叔叔开车从甲地赶往乙地,平均每小时行驶 62 千米,3 小时到达。 甲、乙两地相距多少千米?
①3 箱可乐共有多少瓶?
②买 2 箱可乐要多少元?
(2) 张叔叔开车从甲地赶往乙地,平均每小时行驶 62 千米,3 小时到达。 甲、乙两地相距多少千米?
答案
答案略
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