| As carbonate rocks weather, the insoluble fractions are introduced into the cave deposits. |
| Finding least common multiples is a preliminary step in adding and subtracting fractions with unlike denominators. |
| The least common denominator for two fractions is the least common multiple of their denominators. |
| These include counting beanbags to learn how to add whole numbers, and folding paper strips to learn to deal with fractions. |
| Finding the least common multiple is an important skill for further dealings with fractions. |
| In particular Zhang sees the reduction of fractions to a common denominator as hard. |
