12.06+5.07+2.94 30.34+9.76-10.34
33×3÷×3 25×7×4
88
2×0.8 ÷ 1.25 ÷344÷1.7 343 17 +-7 ×1027.3÷5.1
3 7717
557 1 --
,
9913
a+b+c=a+ (b + c ), a+b-c=a +(b-c), a-b-c= a-( b +c); –a-b+c=a (b-c),
933-15.7-4.3 20.28 -19.72-41.06
233455 8+2- -73+
889975
322 +7+311
553
a×b÷c=a×(b÷c), a÷b÷c), a×b×c=a×(b×c=a÷(b×c) ,
c),
b×c=a÷(b÷a÷ ÷0.4 ÷ 18.62.5 14700÷÷5
2.5 1.06 ××4 4 0.51.96÷÷
13131717
27271919 × 29÷ ×13÷
a +(b-c)= a+b-c a+ (b + c )= a+b+c
a –(b-c)= a-b+c a-( b +c)= a-b-c; 19.68-(2.68+2.97) 5.68+(5.39+4.32)
252+(- 7) -(19.682.97+9.68)
171817
163)
-(5-
877
c, b a×(÷c) = a×b÷ a×(b×c) = a×b×c, a÷(b÷c) = a÷b×c, ÷b×a÷(c) = a÷bc ,
8 1.25×( ÷0.5) 0.25×( 4 ×1.2)
74100 ) ) × × 1.25×(2130.8) 0.74÷(4÷ 9.3÷(71
10093
5133191121 24 7( - -( × )-× 7 (12+) × ) + 20835386712
71673 ×- 8.59 ×0.92+×0.921.41×
513513
99×11.6+18.4× ×11.6-1.6×1.3 1.3 55
9999+999+99+9 4821-998
3.6 1.25×88 ×0.25 3.2×12.5×25