from the box front:
Mummbly
General Knowledge
A Game of Chance & Trivia

from the box back:
Roll the Dice,
Knock Down the Numbers,
Answer the Questions
& Score

from the manufacturer's website (www.mummbly.ca)
Mummbly Chance - This is a low score dice game that involves concealing a number or any one combination of numbers in the series according to the sum of the dice toss.
Mummbly Trivia - This is a high score trivia dice game that involves concealing a number or any one combination of numbers in the series according to the sum of the dice toss, and collecting valued trivia cards.

This game is very similar to Double Shutter. The game box starts with the numbers 1-9 flipped up. You roll two d6 and add them together. You then flip down enough numbers to add up to the total you rolled. Once you roll a number that can't be summed up by numbers still showing, you score by counting and summing these remaining numbers. This is the Mumbly Chance game. Mumbly Trivia adds Trivial Pursuit-like cards to the gameplay.