In this Grade 4 Saxon Math lesson from Chapter 6, students learn how to read and interpret a calendar, including the concepts of common years, leap years, decades, and centuries, as well as how to calculate the difference between two years using a later-minus-earlier equation. Students also practice rounding multi-digit numbers to the nearest thousand by identifying the hundreds digit and locating the number between two consecutive multiples of 1000 on a number line. These two skills are taught together through real-world contexts such as historic dates and ticket sales figures.
Section 1
📘 The Calendar, Rounding Numbers to the Nearest Thousand
To round a number to the nearest thousand, we find the multiple of to which the number is closest.
Next, you'll use a number line and place value to practice rounding numbers to the nearest thousand, hundred, and ten.
Section 2
The Calendar
A year is the time Earth takes to orbit the sun, about days. We have common years with 365 days and leap years with 366 days. A decade is ten years and a century is one hundred years. The jingle “Thirty days have September, April, June, and November” helps remember which months have 30 days.
How many days are in a leap year? A leap year has 366 days.
How many days does December have? It's not in the “Thirty days” jingle, so it has 31 days.
How many years are in 5 decades? years.
Think of the calendar as our planet's personal diary! To keep the seasons in sync, we add an extra day every four years in a leap year to account for that pesky quarter-day. This clever jingle helps you remember which months are shorter, so you're never caught off guard when making plans.
Section 3
Later − earlier = difference
To find the amount of time between two years, we use subtraction. Instead of thinking 'larger-smaller=difference,' we think of 'later-earlier=difference.' We subtract the earlier date from the later date to find the number of years between those two historic events. The formula is: Later − Earlier = Difference. This is used to compare two numbers, specifically years.
Find the years between 1812 and 1865. years.
Calculate the time from 1918 to 1943. years.
How many years passed between the founding of Rome in 753 BC and its fall in 476 AD? years.
Ever wonder how many years passed between two historical events? It's just simple subtraction! Take the more recent year and subtract the older year from it. This trick turns history into a math problem, giving you the exact time gap. No time machine needed for this calculation, just some simple math!
Section 4
Rounding Numbers to the Nearest Thousand
To round a number to the nearest thousand, you must find which multiple of 1000 the number is closest to, like 1000, 2000, 3000, and so on. A simple way is to check the hundreds digit. If the digit is 5 or more, you round up. If it is 4 or less, you round down.
Round 7,836 to the nearest thousand. The hundreds digit is 8, so we round up to 8000.
Round 34,186 to the nearest thousand. The hundreds digit is 1, so we round down to 34,000.
Round 21,694 to the nearest thousand. The hundreds digit is 6, so we round up to 22,000.
Rounding to the nearest thousand is like finding the closest major city on a map. Is 7,836 closer to '7000 City' or '8000 City'? The hundreds digit is your guidepost: if it's 5 or more, that means you are over halfway there, so you round up to the next biggest city!
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Section 1
📘 The Calendar, Rounding Numbers to the Nearest Thousand
To round a number to the nearest thousand, we find the multiple of to which the number is closest.
Next, you'll use a number line and place value to practice rounding numbers to the nearest thousand, hundred, and ten.
Section 2
The Calendar
A year is the time Earth takes to orbit the sun, about days. We have common years with 365 days and leap years with 366 days. A decade is ten years and a century is one hundred years. The jingle “Thirty days have September, April, June, and November” helps remember which months have 30 days.
How many days are in a leap year? A leap year has 366 days.
How many days does December have? It's not in the “Thirty days” jingle, so it has 31 days.
How many years are in 5 decades? years.
Think of the calendar as our planet's personal diary! To keep the seasons in sync, we add an extra day every four years in a leap year to account for that pesky quarter-day. This clever jingle helps you remember which months are shorter, so you're never caught off guard when making plans.
Section 3
Later − earlier = difference
To find the amount of time between two years, we use subtraction. Instead of thinking 'larger-smaller=difference,' we think of 'later-earlier=difference.' We subtract the earlier date from the later date to find the number of years between those two historic events. The formula is: Later − Earlier = Difference. This is used to compare two numbers, specifically years.
Find the years between 1812 and 1865. years.
Calculate the time from 1918 to 1943. years.
How many years passed between the founding of Rome in 753 BC and its fall in 476 AD? years.
Ever wonder how many years passed between two historical events? It's just simple subtraction! Take the more recent year and subtract the older year from it. This trick turns history into a math problem, giving you the exact time gap. No time machine needed for this calculation, just some simple math!
Section 4
Rounding Numbers to the Nearest Thousand
To round a number to the nearest thousand, you must find which multiple of 1000 the number is closest to, like 1000, 2000, 3000, and so on. A simple way is to check the hundreds digit. If the digit is 5 or more, you round up. If it is 4 or less, you round down.
Round 7,836 to the nearest thousand. The hundreds digit is 8, so we round up to 8000.
Round 34,186 to the nearest thousand. The hundreds digit is 1, so we round down to 34,000.
Round 21,694 to the nearest thousand. The hundreds digit is 6, so we round up to 22,000.
Rounding to the nearest thousand is like finding the closest major city on a map. Is 7,836 closer to '7000 City' or '8000 City'? The hundreds digit is your guidepost: if it's 5 or more, that means you are over halfway there, so you round up to the next biggest city!
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter