The less cynical answer (in my opinion), would be that they weren't writing a math book, they were writing a book about faith and spirituality so they really weren't concerned with making all the math add up.  I know this might come as a shock to some in the religious community, but perhaps parables aren't meant to be taken literally.  The were meant as abstract lessons about how to live one's life in a moral way, not how to acquire religious OCD.  

That's the difference between regular folks like us and folks like Moses-:) or even, perhaps, folks like MLK.

In general, prophets are able to see into the future without problem and tend to accept their end as God's will.

And when you're talking about God, the arrow of time doesn't apply.

The following is a story behind those myths . . .

This is a wee bit before the Hebrew Scribes started work on their scrolls.

Have a good time deciphering the true meaning of the tale.

Enûma Eliš - "When on High" circa 1100 B.C.E.

When on high the heaven had not been named,
Firm ground below had not been called by name,
Naught but primordial Apsu, their begetter,
(And) Mummu-Tiamat, she who bore them all,
Their waters commingling as a single body;
No reed hut had been matted, no marsh land had appeared,
When no gods whatever had been brought into being, 

Uncalled by name, their destinies undetermined-
Then it was that the gods were formed within them.
Lahmu and Lahamu were brought forth, by name they were called.
For aeons they grew in age and stature.
Anshar and Kishar were formed, surpassing the others.
They prolonged the days, added on the years.
Anu was their son, of his fathers the rival;
Yea, Anshar's first born, Anu was his equal.
Anu begot in his image Nudimmud.
This Nudimmud was of his fathers the master;
Of broad wisdom, understanding, mighty in strength,
Mightier by far than his grandfather, Anshar.
He had no rival among the gods, his brothers.

The divine brothers banded together,
They disturbed Tiamat as they surged back and forth,
Yea, they troubled the mood of Tiamat
By their hilarity in the Abode of Heaven.
Apsu could not lessen their clamour
And Tiamat was speechless at their ways.
Their doings were loathsome unto (. . .).
Unsavory were their ways; they were overbearing.
Then Apsu, the begetter of the great gods,
Cried out, addressing Mummu, his vizier:
"O Mummu. my vizier, who rejoicest my spirit,
Come hither and let us go to Tiamat!"
They went and sat down before Tiamat,
Exchanging counsel about the gods, their first born.
Apsu, opening his mouth,
Said unto resplendent Tiamat:
"Their ways are verily loathsome unto me.
By day I find no relief, nor repose by night.
I will destroy, I will wreck their ways,
That quiet may be restored. Let us have rest!"
As soon as Tiamat heard this,
She was wroth and called out to her husband.
She cried out aggrieved, as she raged all alone,
Injecting woe into her mood:
"What? Should we destroy what we have built?
Their ways are indeed troublesome, but let us attend kindly!"
Ill wishing and ungracious was Mummu's advice:
"Do destroy, my father, the mutinous ways.
Then shalt thou have relief by day and rest by night!"

When Apsu heard this, his face grew radiant
Because of the evil he planned against the gods, his sons.
As for Mummu, by the neck he embraced him
As (that one) sat down on his knees to kiss him.
(Now) whatever they plotted between them
Was repeated unto the gods, their first born.
When the gods heard (this), they were astir,
(Then) lapsed into silence and remained speechless,
Surpassing in wisdom, accomplished, resourceful,
Ea, the all wise, saw through their scheme.

A master design against it he devised and setup,
Made artful his spell against it, surpassing and holy.
He recited it and made it subsist in the deep,
As he poured sleep upon him. Sound asleep he lay.

When Apsu he made prone, drenched with sleep,
Mummu, the adviser, was impotent to move,
He loosened his band, tore off his tiara,
Removed his halo (and) put it on himself.

Having fettered Apsu, he slew him.
Mummu he bound and left behind lock.
Having thus upon Apsu established his dwelling,
He laid hold on Mummu, holding him by the nose rope.

After he vanquished and trodden down his foes,
Ea, his triumph over his enemies secured,
In his sacred chamber in profound sleep he rested.

He named it "Apsu," for shrines he assigned (it).

In that same place his cult hut he founded.
Ea and Damkina, his wife, dwelled (there) in splendor.
In the chamber of fates, the abode of destinies,
A god was engendered, most potent and wisest of gods.
In the heart of Apsu was Marduk created,
In the heart of holy Apsu was Marduk created.
He who begot him was Ea, his father;
She who conceived him was Damkina, his mother.
The breast of goddesses did she suck.

The nurse that nursed him filled him with awesomeness.
Alluring was his figure, sparkling the lift in his eyes.
Lordly was his gait, commanding from of old.
When Ea saw him, the father who begot him,
He exulted and glowed, his heart filled with gladness.

He rendered him perfect and endowed him with a double godhead.
Greatly exalted was he above them, exceeding throughout.
Perfect were his members beyond comprehension,
Unsuited for understanding, difficult to perceive.
Four were his eyes, four were his ears;
When he moved his lips, fire blazed forth.
Large were all hearing organs,
And the eyes, in like number, scanned all things.
He was the loftiest of the gods, surpassing was his stature;
His members were enormous, he was exceedingly tall.

"My little son, my little son!
My son, the Sun! Sun of the heavens!"
Clothed with the halo of the ten gods, he was strong to the utmost,
As their awesome flashes were heaped upon him.

Disturbed was Tiamat, astir night and day.
The gods, in malice, contributed to the storm.
Their insides having plotted evil.
To Tiamat these brothers said:
"When they slew Apsu, thy consort,
Thou didst not aid him but remaindest still.
Although he fashioned the awesome Saw,
Thy insides are diluted and so we can have no rest.
Let Apsu, thy consort, be in thy mind
And Mummu, who has been vanquished! Thou are left alone.

Then joined issue Tiamat and Marduk, wisest of gods,
They swayed in single combat, locked in battle.
The lord spread out his net to enfold her,
The Evil Wind, which followed behind, he let loose in her face.
When Tiamat opened her mouth to consume him,
He drove the Evil Wind that she close not her lips.
As the fierce winds charged her belly,
Her body was distended and her mouth was wide open.
He released the arrow, it tore her belly,
It cut through her insides, splitting the heart.
Having thus subdued her, he extinguished her life.
He cast down her carcass to stand upon it...
The lord trod on the legs of Tiamat,
With his unsparing mace he crushed her skull.

When the arteries of her blood he had severed,
The North Wind bore (it) to places undisclosed.
On seeing this, his fathers were joyful and jubilant,
They brought gifts of homage, they to him.
Then the lord paused to view her dead body,
That he might divide the monster and do artful works.

He split her like a shellfish into two parts:
Half of her he set up and ceiled as sky,
Pulled down the bar and posted guards.
He bade them to allow not her waters to escape.

He crossed the heavens and surveyed (its) regions.
He squared Apsu's quarter, the abode of Nudimmud,
As the lord measured the dimensions of Apsu.
The Great Abode, its likeness, he fixed as Esharra,
The Great Abode, Esharra, which he made as the firmament.
Anu, Enlil, and Ea he made occupy their places.

When Marduk hears the words of the gods,
His heart prompts (him) to fashion artful works.

Opening his mouth he addresses EA
To impart the plan he addresses EA

To impart the plan he had conceived in his heart:
"Blood I will mass and cause boned to be.
I will establish a savage, 'man' shall be his name.

Verily, savage man I will create.
He shall be charged with the service of the gods
That they might be at ease! The ways of the gods I will artfully alter.
Though alike revered, into two (groups) they shall be divided."
 

Ea answered him, speaking a word to him.
To relate to him a scheme for the relief of the gods:
"Let but one of their brothers be handed over;"
He alone shall perish that mankind may be fashioned.

Let the great gods be here in Assembly,
Let the guilty be handed over that they may endure."
 

Marduk summoned the great gods to Assembly;
Presiding graciously, he issued instructions.
This utterance the gods pay heed.

The king addresses a word to the Anunnaki:
"If your former statement was true,
Do (now) the truth on oath by me declare!
Who was it that contrived the uprising,
And made Tiamat rebel, and joined battle?
Let him be handed over who contrived the uprising.
His guilt I will make him bear that you may dwell in peace!"

The Igigi, the great gods, replied to him,
To Lugaldimmerankia, counsellor of the gods, their lord:
"It was Kingu who contrived the uprising,
And made Tiamat rebel, and joined battle."
The bound him holding him before Ea.

They imposed on him his guilt and severed his blood (vessels).
Out of his blood they fashioned mankind.
He imposed the service and let free the gods.

~OGD~

.

But if you use base 12, as the English did for their money a while back, you get almost all that minus the 5. No?