Sales Managers have asked for an at-a-glance solution to see completeness on leads. Create a helper formula field that looks at 5 key fields on the Lead object and evaluates their completeness, then a second formula field that references the helper formula and returns an image.

>The helper formula field should be on the Lead object with a name of 'Lead Quality Helper' and a resulting API name of 'Lead_Quality_Helper__c'.
>The helper formula should be of type Number.
>The helper formula should evaluate the following 5 fields: Email, Phone, Company, Title, and Industry and return 0 if blank and 1 if not blank. >The formula should then add all the values together to return a total value.
>The image formula should be on the Lead object with a name of 'Lead Quality' and a resulting API name of 'Lead_Quality__c'.
>The image formula should reference the helper formula, and return an image based on the number returned by the helper formula. The helper formula should be of type Text. Note: All of these images are already available in your Developer Edition.

1 = /img/samples/stars_100.gif with alternate text '1 star'
2 = /img/samples/stars_200.gif with alternate text '2 stars'
3 = /img/samples/stars_300.gif with alternate text '3 stars'
4 = /img/samples/stars_400.gif with alternate text '4 stars'
5 = /img/samples/stars_500.gif with alternate text '5 stars'

If none of the fields are filled out, the default should be /img/samples/stars_000.gif with alternate text '0 stars'.
The 'Lead Quality' formula must be added to the Lead Layout page layout.

ok so im having trouble on this challenege on trailhead. im confused what it means by helper formula, like how would we create a helper formular? also how would we create a image formula?

thanks if anyone answers 

I am getting error message while solving this challenge in Trailhead :

To complete this challenge, add a validation rule which will block the insertion of a contact if the contact is related to an account and has a mailing postal code (which has the API Name MailingPostalCode) different from the account's shipping postal code (which has the API Name ShippingPostalCode).Name the validation rule 'Contact must be in Account ZIP Code'.
A contact with a MailingPostalCode that has an account and does not match the associated Account ShippingPostalCode should return with a validation error and not be inserted.
The validation rule should ONLY apply to contact records with an associated account. Contact records with no associated parent account can be added with any MailingPostalCode value. (Hint: you can use the ISBLANK function for this check)

Error Message is :  There was an unhandled exception. Please reference ID: HKIZNLVZ. Error: Trailhead::TrailheadTimeOut. Message: Trailhead.view: failed to get a 200 response. Made 3 attempts each resulting in a 403 or 500 failure for url challenges?key=%5B%22trailhead.challenge.validation_rules.en.us.192%22%5D.

I am not sure what went wrong here.
My Validation Rule is on Contact Object  :

  AND ( NOT(ISBLANK( Account.Name)),
( MailingPostalCode <> Account.ShippingPostalCode))

Can anyone please help with this.