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Rational Numbers
Let's Recall In our previous grades, we learned about natural numbers and whole numbers. We know that integers are positive and negative whole numbers. We also know how to read, write and represent fractions and decimals. We know that these are all rational numbers. Let us recap how to add and subtract integers, fractions and decimals. Adding Integers
Subtracting Integers
Like Sign
Unlike Sign
Add and keep the sign.
Subtract and keep the larger number sign.
4+2=6
Change the sign of subtrahend and solve. –3 – (–2) = –3 + 2 = –1
(–4) + 3 = –1
(–4) + (–2) = –6 Adding and Subtracting Decimals • Convert to like decimals • Align the decimal points • Add or subtract 1 2 .6 3 + 1 .3 0 1 3 .9 3
1 2 .6 3 − 1 .3 0 1 1 .3 3
Adding and Subtracting Fractions Like Fraction
Unlike fraction
• Add or subtract the numerators.
• Convert to like fraction by taking the LCM.
• Keep the common denominator.
• Add or subtract as done in like fractions.
2 4 2+4 6 + = = 5 5 5 5
2 2 10 − 6 4 – = = 3 5 15 15
Letʼs Warm-up Fill in the blanks. 5 + 2 4 3
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2 52.31 + 61.2
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3 − 23 + 69
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4
7 − 5 8 4
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5 89 − 47.25
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I scored _________ out of 5.