import tensorflow as tf

a = tf.placeholder(tf.float32)
b = tf.placeholder(tf.float32)
adder_node = a + b

sess = tf.Session()

print("adder_node >>", sess.run(adder_node, feed_dict={a:3, b:4.5}))
print("adder_node >>", sess.run(adder_node, feed_dict={a:[1,3], b:[2,4]}))

add_and_triple = adder_node * 3
print("adder_and_triple >>", sess.run(add_and_triple, feed_dict={a:3, b:4.5}))