2026年学生基础性作业四年级数学上册人教版第42页答案
轻松算吧
$190 × 7 =$
$208 × 90 =$
$125 × 40 =$
$48 × 48 ÷ 48 =$
$50 × 80 =$
$205 × 30 =$
$25 × 400 =$
$760 - 280 ÷ 4 =$

答案

1. 1330
2. 18720
3. 5000
4. 48
5. 4000
6. 6150
7. 10000
8. 690
1. 根据规律写出最后两个算式的得数。
88 × 81 = 7128
888 × 81 = 71928
8888 × 81 = 719928
88888 × 81 = (
7199928
)
888888 × 81 = (
71999928
)

答案

1. 7199928 71999928
2. 先用计算器计算各算式的得数，找出规律后再写一个类似的算式。
$9 × 9 =$
$99 × 99 =$
$999 × 999 =$
$9999 × 9999 =$
99999 × 99999 = 9999800001

答案

2. 81 9801 998001 99980001
99999 × 99999 = 9999800001
3. 先用计算器计算每组前三个算式的得数，再根据规律写出其他算式的得数。
(1) $99 × 2 =$
$999 × 2 =$
$9999 × 2 =$
$99999 × 2 =$
$999999 × 2 =$
(2) $12 × 21 =$
$112 × 211 =$
$1112 × $$2111 =$
$11112 × 21111 =$
$111112 × 211111 =$

答案

3. (1) 198 1998 19998 199998 1999998
(2) 252 23632 2347432 234585432 23456965432
4. 超强计算机可以学习并识别出常见的数学模式和规律，从而更快地得出计算结果。请你找出计算机所捕捉到的规律，并补全下面的算式。
19 + 9 × 9 = 100
118 + 98 × 9 = 1000
1117 + 987 × 9 = 10000
11116 + 9876 × 9 = (
100000
)
(
111115
) + (
98765
) × 9 = (
1000000
)

答案

4. 100000 111115 98765 1000000