Answer:
Jeez this is a big question
Step-by-step explanation:
1. if they are rounded to the nearest 10 that would mean that it is actually
40 * 40
40 * 40 is 1600. The answer for #1 is 1600
2. its just asking what 21 x3 is, 21x3 is 63
3. All you do for this is 20*23
20 * 23 is 460
4. 42 * 31 is 1302
5. 22 * 95 = 2090
6. You do 20x2 which is 40 and then you do 8x2 which is 16
Adding
then you have 40 + 16 = 56
Subtracting
40 - 16 = 24
Multiplying
40 * 16 = 640
Dividing
40/16 = 2.5
7. 33x2 is 66
8. 57* 4 is 228
9. 128 * 11 is 1408 but if you round the 11 to the nearest 10, that would be 10, then if you round the 128 to the nearest 10, that would be 130, and then 130 * 10 is 1300