Proyecto Salón Hogar
S k i l l i n A r i t h m e t i c
Internet Explorer 6 is the browser to view
these pages, and Garamond is the font.
Sums less than 10. Composing 10 itself.
Sums between 10 and 20. Zero.
The Multiplication Table
Powers of 10
Which numbers are the powers of 10?
How do we read a whole number?
What do we mean by the place value
of a digit?
How do we write a whole number in expanded form?
How do we round off a whole number to a given place?
How do we multiply a whole number by a power of 10?
The Meaning of Decimals
Which numbers are the decimal units? What is the function of the decimal point?
How do we read a decimal? How do we compare decimals?
||Multiplying by Powers of 10
Dividing by Powers of 10
The Meaning of Percent
How do we multiply a decimal by a power of 10? How do we
divide a decimal by a power of 10?
When is a number written in "scientific notation"?
What does "percent" mean?
How can we take 1% of a number?
||More Elementary Addition
How do we add mentally by composing a multiple of 10? How do we add by endings? How do we add the units from left to right? How can we add by rounding off?
||Adding Whole Numbers and Decimals
Addition with Regrouping
How do we add whole numbers?
How do we add decimals?
||The Meaning of Subtraction
What is the problem in subtraction?
How can we find the difference between a one-digit and a two-digit number?
How can we find the difference between two-digit numbers?
How do we complete 100? How can we find the difference by rounding off?
||Subtracting Whole Numbers and
How do we subtract by compensating?
How do we subtract by regrouping?
||The Meaning of Muliplication
What is "multiplication"?
How do we multiply whole numbers that end in 0's?
What is the distributive property of multiplication, and how can we apply it to mental calculation?
How can we multiply mentally by rounding off?
||Multiplying Whole Numbers,
In writing, how do we multiply whole numbers?
How do we multiply decimals?
How can we find a percent of a number?
How can we find the area of a rectangle?
The Meaning of Division
The divisor, the dividend, and the quotient.
What is the problem in division?
What is a rate?
Exact versus inexact division.
The divisor a decimal.
How do we divide by decomposing the dividend?
How do we do short division?
How do we proceed when the dividend is a decimal?
How do we round off a decimal to a given number of decimal places?
How do we express the quotient as a decimal?
When the divisor is a decimal, what must we do?
Percent with a Calculator
How do we use a calculator to solve a percent problem?
Parts of Natural Numbers 1
Which numbers are the natural numbers?
What does it mean to say that a smaller number is a part of a
What does it mean to say that a smaller number is parts
(plural) of a larger number?
Percents are parts of 100%.
Parts of Natural Numbers 2
What do we mean by a mixed number of times?
How can we find a part by dividing?
How can we find a fifth or 20% of a number?
What percent means a third?
How can we take half of any
How can we take a fourth or 25% of a number?
How can we multiply by 5 or 15?
Increase or decrease by a part.
Ratio and Proportion 1
What do we mean by the ratio of two natural
How do percents express ratios?
What is a proportion?
When is a ratio expressed with the lowest terms?
What is the
Theorem of the Common Divisor?
Ratio and Proportion 2
What is the Theorem of the Alternate Proportion? What is
the Theorem of the Same Multiple?
What percent of 100 is any number?
What does it mean to say that two quantities are directly
proportional? How do we solve problems of
What does it mean to say that two quantities are inversely
||Proper Fractions, Mixed Numbers,
A fraction is a number that we need for measuring.
What is a common fraction? What is a proper
fraction? How do we name the proper fractions?
What ratio has each fraction to 1?
What is a mixed number?
What is an improper fraction?
What is a unit fraction?
How can we express a whole number as a fraction?
What do we mean by the complement of a proper fraction?
What kind of fraction does "out of" indicate?
What are equivalent fractions? How can we know when
fractions are equivalent?
How can we reduce a fraction to its lowest terms? How can we reduce a fraction in which the numerator or denominator is a decimal?
How can we compare fractions with the same
numerator? How can we compare fractions with the same
How can we find the lowest common multiple of two numbers?
How can we compare fractions when the
numerators and denominators are different?
How can we know whether a fraction is more than or less than ½?
Fractions into Decimals
What is a "decimal"? How can we change a fraction to a decimal?
Frequent decimals and frequent percents: Half, thirds, quarters, fifths, eighths.
Complete versus incomplete decimals.
Adding and Subtracting Fractions
How do we add or subtract fractions?
What number should we
choose as the common denominator?
How do we add mixed numbers?
How do we subtract a mixed
number from a whole number?
How do we multiply a fraction by a whole number? How do
we multiply a fraction by a fraction?
How do we divide fractions?
Lesson 26 The Meaning of Multiplying Fractions
Parts of Fractions
What does it mean to multiply a number by a
How can we express a fraction as a percent?
How can we take a part of a fraction?
Percents are Ratios
How do percents express ratios?
Percent increase or decrease. Estimations.
Percent of a Number
How can we find the Amount?
What does ½% mean?
How can we find the Base?
The Method of Proportions
How can we find the Percent by the method of proportions?
What is a general method for finding the Percent?
Percent Increase or Decrease
"Out of" problems and "difference" problems.
In a banking problem, what is the Amount and what is the Base?
What is a prime number? How can we find the prime factorization of a number?
Is there a last prime?
||Greatest Common Divisor
Lowest Common Multiple
How can we find the GCD and the LCM of two numbers from their prime factorizations?