Rounding to 1 Decimal Place and Finding Highest Common Factors

This page covers two important mathematical concepts: rounding to one decimal place and finding the highest common factor. The content begins with an explanation of how to round numbers to one decimal place using the "5 or more" rule. It then moves on to discuss the highest common factor (HCF) and how to find it using factor trees. The page also touches on the concept of lowest common multiple (LCM).

Definition: Rounding to 1 decimal place means adjusting a number to the nearest tenth.

Highlight: When rounding to 1 decimal place, look at the second decimal digit (the "decider"). If it's 5 or more, round up; if it's 4 or less, round down.

Example: 4.8425 rounded to 1 decimal place is 4.8 because the decider (4) is less than 5.

The page provides several examples of rounding to one and two decimal places:

• 5.267 rounds to 5.3 (1DP)
• 4.8325 rounds to 4.83 (2DP)
• 1.967 rounds to 2.0 (1DP)
• 4.8595 rounds to 4.86 (2DP)
• 8.973 rounds to 9.0 (1DP)

Definition: The Highest Common Factor (HCF) is the largest number that divides exactly into two or more numbers.

The page demonstrates how to find the HCF of 50 and 80 using factor trees:

• 50 = 2 x 5 x 5 (2 x 5²)
• 80 = 2 x 2 x 2 x 2 x 5 (2⁴ x 5)

Example: The HCF of 50 and 80 is 10 (5 x 2).

The page also mentions that factors can be listed and compared to find the HCF.

Vocabulary: Lowest Common Multiple (LCM) is the smallest number that is a multiple of two or more numbers.

The page includes a brief mention of the LCM of 50 and 80, which is 400.

Highlight: Factor trees and prime factorization are useful tools for finding both the HCF and LCM of numbers.

This comprehensive overview provides students with essential skills for working with decimals and factors, which are crucial for more advanced mathematical concepts in algebra and beyond.