a) 198 + 232 - 98 - 32 = (232 - 32) + (198 - 98) = 300.
b) 567 - 32 - 68 = 567 - (32 + 68) = 467.
c) 99 - 97 + 95 - 93 + 91 - 89+ ...+7 - 5 + 3 - 1
= (99 - 97) + (95 - 93) + (91 - 89) +... + (7 - 5) + (3 -1)
= 2 + 2 + 2 + . .. + 2 + 2 = 2.25 = 50.
tính nhanh:a)2.31.12+4.6.42+8.27.3
b)36.28+36.82+64.69+64.41
c)99-97+95-93+91-89+..............+7-5+3-1
S = 99 – 97 + 95 – 93 + 91 – 89 + ….+11 – 9 + 7 – 5 + 3 – 1S = 99 – 97 + 95 – 93 + 91 – 89 + ….+11 – 9 + 7 – 5 + 3 – 1
a) 3^6÷3^2+2^3×2^2
b) (2100-63)÷21
c) 32×59+41×32
d) 99-97+95-93+91+89+...+9-5+3-1
Tính nhanh: C=99-97+95-93+91-89+....7-5+3-1
Tính nhanh: 99 - 97 + 95 - 93 + 91- 89 + ... + 7 - 5 + 3 - 1
Tính:99 - 97 + 95 - 93 +91 - 89 + ... + 7 - 5 + 3 - 1 =............
Tính nhanh; 99-97+95-93+91-89+....+7-5+3-1
Tính nhanh: 99- 97 + 95 - 93 + 91 - 89 +...+ 7 - 5 + 3 - 1.
tính nhanh: 99-97+95-93+91-89+...+7-5+3-1
