Composition and calculation: hundredths and thousandths

Introduction

Building on segment 1.23, introduce children to hundredths (and thousandths) using both the partitioning structure and ideas of place value; apply additive facts and strategies, including column algorithms, and rounding to numbers with hundredths (and thousandths).

Teaching points

• Teaching point 1: When one is divided into 100 equal parts, each part is one hundredth of the whole. When one tenth of a whole is divided into ten equal parts, each part is one hundredth of the whole.
   
• Teaching point 2: Hundredths can be expressed as decimal fractions; the number written ‘0.01’ is one hundredth; one is one hundred times the size of 0.01; 0.1 is ten times the size of 0.01.
   
• Teaching point 3: We can count in hundredths up to and beyond one.
   
• Teaching point 4: Numbers with hundredths can be composed additively and multiplicatively.
   
• Teaching point 5: Numbers with tenths and hundredths are commonly used in measurement, scales and graphing contexts.
   
• Teaching point 6: Known facts and strategies, including column algorithms, can be applied to calculations for numbers with hundredths; the same approaches can be used for numbers with hundredths as are used for numbers with tenths.
   
• Teaching point 7: Numbers with hundredths can be rounded to the nearest tenth by examining the value of the hundredths digit or to the nearest whole number by examining the value of the tenths digit.
   
• Teaching point 8: When one is divided into 1,000 equal parts, each part is one thousandth of the whole. Knowledge and strategies for numbers with tenths and hundredths can be applied to numbers with thousandths.