两位数乘整十数的口算与估算（课件）-2023-2024学年三年级下册数学苏教版

两位数乘整十数 口算和估算 1 2 2×3=6 2个一 6个一 ×3= 个 4 想：2×3=6 20×3=60 2个十 6个十 ×3= 0 0 十 想：2×3=6 200×3=600 2个百 6个百 ×3= 00 00 百 2×3=6 2个一×3是6个一 想：2×3=6 20×3=60 想：2×3=6 200×3=600 2个十×3是6个十 2个百×3是6个百 12×3= 2×3=6 10×3=30 30＋6=36 36 1 2 3 4 5 6 7 8 9 10 11 12 10 9 8 7 6 5 4 3 2 1 每10个一串， 12串一共有多少个鸡蛋？ 12×10= 材料一： 材料三： 我这样想：先算______________ 再算______________ 材料二： 12个十 12×10= 想：先算12 × 1 = 12 1个十 12个十 0 120 10×10=100 10×2=20 100＋20=120 想：先算12×1=12 再算12×10=120 10×10=100 10×2=20 100＋20=120 2×10=20 6×20=120 13×20= 想：13×2=26 260 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● 2个十 26个十 0 0 0 0 21×30= 想：21 × 3 = 63 630 12×10=120 12×20=240 21×30=630 12×10=120 12×20=240 21×30=630 1个十 12个十 2个十 24个十 3个十 63个十 几个十 几个十 32×10= 20×10= 10×55= 30×10= 14×20= 30×20= 320 想：32×1=32 550 想：1×55=55 280 想：14×2=28 200 想：20×1=20 300 想：30×1=30 想：3×1=3 600 想：30×2=60 想：3×2=6 20×10=200 30×10=300 30×20=600 20×10=200 30×10=300 30×20=600 20个十 30个十 60个十 20×10=200 30×10=300 30×20=600 20×10=200 30×10=300 30×20=600 ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● ●●●●●●●●●● 1个百 1个百 1个百 3×1 50×30= 想：5 × 3 = 15 1500 12×20= 240 30×11= 330 20×90= 1800 60×70= 4200 30×80= 2400 80×50= 4000 80×50