Tenths: Slicing Numbers into Ten Equal Pieces

Imagine you have a chocolate bar. It is snapped into 10 equal pieces. You eat 3 pieces. What part of the whole bar did you eat? Think about it for a moment — how would you write that as a number? Share your idea before we explore the answer together.

When you split one whole thing into 10 equal parts, each part is called a tenth. You can write one tenth as the fraction 1/10. You can also write it as the decimal 0.1. A decimal is a way of writing numbers that are smaller than 1. The dot in the middle is called the decimal point. The digit just after the decimal point tells you how many tenths you have. 0.1 means 1 tenth 0.3 means 3 tenths 0.7 means 7 tenths A number line from 0 to 1 can be split into 10 equal jumps. Each jump is one tenth — or 0.1. You can also have tenths sitting after a whole number. For example, 1.4 means 1 whole and 4 tenths. The whole number sits to the left of the decimal point, and the tenths sit to the right. Fractions and decimals are two ways of writing the same amount: • 3/10 is the same as 0.3 • 9/10 is the same as 0.9 • 10/10 is the same as 1.0 (one whole!)