a)=9*3-26

   =27-26

   =1

b)=125*100-25*100

   =12500-2500

   =10000

-84:4+39.37+50
=-12+1443+50
=1481
9.|40-37|-|2.13-52|
=9.l3l-l-26l
=9.3-26
=1

-84:4+3⁹.3⁷+5⁰

=-84:4+3¹⁶+1

=-21+3¹⁶+1

=-21+43046721+1

=43046700+1=43046701

9.|40-37|-|2.13-52|

=9.|3|-|-26|

=9.3-26

=27-26=1

ℓ. 500 – {5[409 – (2³.3 – 21)²] + 10³} : 15

= 500 - {5[409-(8.3-21)²]+10³}:15

= 500-{5[409-(24-21)²]+1000}:15

= 500-{5[409-3²]+1000}:15

= 500-{5[409-9]+1000}:15

= 500-{[5.400]+1000}:15

= 500-{2000+1000}:15

= 500-3000:15

= 500-200

= 300

m. 67 – [8 + 7.3² – 24 : 6 + (9 – 7)³] : 15

= 67 – [8 + 7.9 – 4 + 2³] : 15

= 67 – [8 + 63 – 4 + 8] : 15

= 67 – [71 – 4 + 8] : 15

= 67 – [67 + 8] : 15

= 67 – 75 : 15

= 67 – 5

= 62

n. (–23) + 13 + (–17) + 57

= (–10) + [(–17) + 57]

= (–10) + 40

= 30

o. (–123) + |–13| + (–7)

= [(–123) + (–7)] + |–13|

= (–130) + 13

= (–117)

p. |–10| + |45| + (–|–455|) + |–750|

= 10 + 45 + (–455) + 750

= (10 + 45 + 750) + (–455)

= 805 + (–455)

= 350

42

100%

Ta có: |40 - 37| - |13 - 52|

= 3 - 39

= -36

|40 - 37| - |13 - 52| 

= 3 - 39

= -36

42

100%

\(\text{(-123) +|–13| +(-7)}\)

\(\text{= (-123) + 13 + (-7)}\)

\(\text{= (-110) + (-7)}\)

\(=\text{(-117)}\)

b

a: Số số hạng là:

(40-2):2+1=20(số)

Tổng là:

\(\dfrac{42\cdot20}{2}=42\cdot10=420\)