42, 45, 40, 47 (), (), 36, 51, Don't write what I don't understand, write the formula

42、45、40、47（38 ）、（ 49）、36、51
Look at even and odd terms respectively
Even items 42 40 38 36
Odd term 45 47 49 51

RELATED INFORMATIONS

1. 36,9,42, (), (), 51, () can only add and subtract. Please explain the solution
2. In the fifth grade, oral arithmetic is practiced every day from 42 to 45, 51 to 54
3. Calculation: 108 ° 18 ′ - 56 ° 23 ′=______ ．
4. How to solve 108 ° 18 ′ + 56 ° 23 ′ 40 ″,
5. The solutions of 108 ° 18 '- 56 ° 23' are expressed in degrees
6. 108°18′+56°23′40〃
7. Among the numbers 3, 15, 22, 51, 78, 60, 83, 210, 29 and 56, odd numbers are: even numbers are: prime numbers are: composite numbers are: multiples of 2 The multiples of 3 are: the numbers with factor 5 are () the numbers with 2, 3 multiples are () the numbers with 3, 5 multiples are () the numbers with 2, 3, 5 multiples are () at the same time（
8. There is a set of data: 42, 44, 44, 46, 48, 48, 48, 50, 51, 51, 56______ The mode is______ ．
9. A = - 123.4 - (- 123.5), B = 123.4-123.5, C = 123.4 - (- 123.5), then () A. c＞b＞aB. c＞a＞bC. a＞b＞cD. b＞c＞a
10. A / 5 + B / 4 + C / 3 = 0.4 (1) a / 4 + B / 3 + C / 2 = 0.5 (2) a / 3 + B / 2 + C = 1 (3), 123 forms a system of linear equations with three variables to solve a, B and C
11. 32 and 72, 75 and 25, 80 and 125, 40 and 60, 17 and 51, 14 and 54. What do you find
12. Find the greatest common factors 32 and 72, 75 and 25, 80 and 125, 40 and 60, 17 and 51, 14 and 54 of each group And what did you find
13. The least common multiple of 11 and 13 is () times their greatest common factor
14. The greatest common factor and the least common multiple of 11 and 13
15. The greatest common factor and the least common multiple of 11 and 3
16. Simple calculation of primary school 51 * 1 -- 6 / 0.9
17. 4.9 * 6.8 + 0.51 * 6.8
18. 0 1 3 9 ) 51 The answer is 21
19. What are the numbers in brackets? A, 1 B, 10 C, 53 D, 130
20. Please fill in the most likely numbers in brackets: 3,7,21,51103, () Please give the derivation process