Question

[(13×a+2×7) :4×100-900]:10-9=1​

Answer 1

$[(13 \times a + 2 \times 7) \div 4 \times 100 - 900] \div 10 - 9 = 1$

$[(13 \times a + 2 \times 7) \div 4 \times 100 - 900] \div 10 = 10$

$(13 \times a + 2 \times 7) \div 4 \times 100 - 900 = 100$

$(13 \times a + 2 \times 7) \div 4 \times 100 = 1000$

$(13 \times a + 2 \times 7) \div 4 = 10$

$13 \times a + 14 = 40$

$13 \times a = 26$

$a = 2$