2025年口算训练四年级数学上册人教版双色升级版第87页答案
$80×2
180$
$850×2
1600$
$9999×0
9999$
$1000×9
2000$
$89
85×9$
$8504
850×4$
$2700
2700+700$
$58×7
57×8$
$84×3
384$
$125×8
250$
$209×7
200$
$3812
58×2$
$1000
10×200$
$306×9
369$
$57×6
570$
$2000×2
1000$
$250×4
2500$
$34×3
34×7$
$21×12
22×11$
$1389+1
1389×1$

答案

解析:本题考查了整数的乘法运算以及大小比较。
$80 × 2 = 160$,$160<180$,所以$80 × 2<180$;
$850 × 2 = 1700$,$1700>1600$,所以$850 × 2>1600$;
$9999 × 0 = 0$,$0<9999$,所以$9999 × 0<9999$;
$1000 × 9 = 9000$,$9000>2000$,所以$1000 × 9>2000$;
$85 × 9 = 765$,$89<765$,所以$89<85 × 9$;
$850 × 4 = 3400$,$8504>3400$(此处原题目可能存在错误,按照正常计算逻辑,应为比较$850 × 4$与$8504$的大小,
原题目中$8504$后多了个与比较式无关的数,按照比较逻辑,我们忽略它),所以$8504>850 × 4$;
$2700 + 700 = 3400$,$2700<3400$,所以$2700<2700 + 700$;
$58 × 7 = 406$,$57 × 8 = 456$,$406<456$,所以$58 × 7<57 × 8$;
$84 × 3 = 252$,$252<384$(或考虑$384$为$3× 128$,显然$84× 3$小于$3× 128$),所以$84 × 3<384$;
$125 × 8 = 1000$,$1000>250$,所以$125 × 8>250$;
$209 × 7 = 1463$,$1463>200$,所以$209 × 7>200$;
$58 × 2 = 116$,$3812>116$,所以$3812>58 × 2$;
$10 × 200 = 2000$,$1000<2000$,所以$1000<10 × 200$;
$306 × 9 = 2754$,$2754>369$,所以$306 × 9>369$;
$57 × 6 = 342$,$342<570$(或直接看出$570$为$57× 10$,显然大于$57 × 6$),所以$57 × 6<570$;
$2000 × 2 = 4000$,$4000>1000$,所以$2000 × 2>1000$;
$250 × 4 = 1000$,$1000<2500$,所以$250 × 4<2500$;
$34 × 3 = 102$,$34 × 7 = 238$,$102<238$,所以$34 × 3<34 × 7$;
$21 × 12 = 252$,$22 × 11 = 242$,$252>242$,所以$21 × 12>22 × 11$;
$1389 + 1 = 1390$,$1389 × 1 = 1389$,$1390>1389$,所以$1389 + 1>1389 × 1$。
答案:<;>;<;>;<;>;<;<;<;>;>;>;<;>;<;>;<;<;>;>。
$82×50$
=
$820×5$
$270×12$
=
$27×120$
$673×50$
$6730$
$62×48$
$62×47$
$400×8$
=
$40×80$
$72×35$
=
$35×72$
$135×40$
=
$1350×4$
$66×73$
$66×74$
$324×3$
$256×4$
$26×14$
$25×15$
$208×40$
$280×40$
$103×34$
$130×43$
$627×3$
$536×2$
$20×240$
=
$200×24$
$547×3$
$548×2$
$50×274$
$5×7240$
$50×897$
=
$5×8970$
$1389+1$
$1389÷1$
$1389-1$
$1389+1$
$1389×1$
=
$1389÷1$

答案

解析:本题主要考察整数的乘法运算以及大小比较。
答案:
$82×50 = 820×5$
$270×12 = 27×120$
$673×50 > 6730$
$62×48 > 62×47$
$400×8 = 40×80$
$72×35 = 35×72$
$135×40 = 1350×4$
$66×73 < 66×74$
$324×3 < 256×4$
$26×14 < 25×15$
$208×40 < 280×40$
$103×34 < 130×43$
$627×3 > 536×2$
$20×240 = 200×24$
$547×3 > 548×2$
$50×274 < 5×7240$
$50×897 = 5×8970$
$1389+1 > 1389÷1$
$1389-1 < 1389+1$
$1389×1 = 1389÷1$