class="bi x0 y0 w1 h1"
class="bi x1 y1 w2 h2"
2 + 3 = 5
(a + b)c = ac + bc ;
class="bi x0 y0 w3 h5"
class="bi x0 y0 w3 h5"
class="bi x0 y0 w4 h5"
class="bi x0 y0 w3 h6"
class="bi x4 y0 w5 h7"
class="bi x0 y0 w6 h5"
class="bi x0 y0 w7 h3"
class="bi x0 y0 w3 h6"
class="bi x2 y0 w8 h8"
class="bi x0 y0 w3 h3"
<
<
≤
∈
a b a < b
a b
b a
b
a b
b a
a b
a b a < b
a b
a b a b
a b <
a < b
a b <

(a < b) (b = c) < (a < c),
(a = b) (b < c) < (a < c),
(a = b) (b − c) < (a = c).
(a < b) (b < c) (c < d) < (a < d),
(a = b) (b = c) (c = d) < (a = d).
a b p
p < a, p < b,
x
x < a, x < b,
x < p.
a b s
a < s, b < s,
s < x.
p s
ab a + b
p s
p
a b s
<
a b a b
a b
a b
ab < a, ab < b,
(x < a)(x < b) < (x < ab),
a < a + b, b < a + b,
(a < x)(b < x) < (a + b < x).
(x < ab)(ab < a) < (x < a),
(x < ab)(ab < b) < (x < b).
(x < ab) < (x < a)(x < b).
(a < a + b)(a + b < x) < (a < x),

(ac < a)(a < b) < (ac < b),
(ac < b)(ac < c) < (ac < bc).
c < b + c,
(a < b)(b < b + c) < (a < b + c).
(a < b + c)(a < b + c) < (a + c < b + c).
(a = b) < (ac = bc), (a = b) < (a + c = b + c).
(a < b)(c < d) < (ac < bd),
(a < b)(c < d) < (a + c < b + d).
(ac < a)(a < b) < (ac < b),
(ac < c)(c < d) < (ac < a),
(ac < b)(ac < d) < (ac < bd).
(a < b)(b < b + d) < (a < b + d),
(c < d)(d < b + d) < (c < b + d),
(a < b + d)(c < b + d) < (a + c < b + d).
(a = b)(c < d) < (ac < bd),
(a = b)(c < d) < (a + c < b + d).
(a = b)(c = d) < (ac = bd),
(a = b)(c = d) < (a + c = b + d).
(a < b) = (a = ab) (a < b) = (a + b = b)
(a < b) < (a = ab), (a < b) < (a + b = b).
(a < a)(a < b) < (a < ab),
(a < b)(b < b) < (a + b < b).
ab < a, b < a + b,
(a < ab)(ab < a) = (a = ab)
(a + b < b)(b < a + b) = (a + b = b).
(a = ab) < (a < b), (a + b = b) < (a < b).
(a − ab)(ab < b) < (a < b),
(a < a + b)(a + b = b) < (a < b).
(a = b) = (ab = a + b).
(a = b) = (a < b)(b < a),

x
x < 1.