Math Review MATH 8 Place Value Hundreds Millions

Math Review MATH 8

Place Value Hundreds Millions Tens 1 Ones 3 13, 652, 10 Thousands Hundreds Tens 6 5 Ones 2 Hundreds 1 Ones Tens 0 Ones 3 thirteen million six hundred fifty two thousand one hundred and three Example: What is the place value of 4 in 6, 342, 105? The 4 is in the ten-thousands place Example: Write the value of two million, five hundred thousand, thirty six 2, 500, 036

Rounding ones hundredths 4 2 9. 6 2 5 tens Round tenths thousandths 3. 9264 to the nearest hundredth 3. 9264 6 is bigger than 5 so round up 3. 93 Don’t put any numbers after the hundredth position

Rounding Round 5. 65394 to the nearest hundredth 5. 65394 3 is smaller than 5 so stays the same 5. 65 Round 18. 42859 to the nearest thousandth 18. 42859 5 is same as 5 so round up 18. 429 Round 5. 99526 to the nearest hundredth 5. 99526 5 is same as 5 so round up, 9 goes to zero so carry over the rounding 6. 00 Keep “ 0” because we need to show we rounded to the nearest hundredth

Addition & Subtraction Add 4. 92 & 3. 55 6. 85 + 3. 91 Line up the number in columns 4. 92 10. 76 + 3. 55 8. 47 Subtract 2. 96 from 5. 33 42 1 1 5. 33 4. 82 - 3. 95 0. 87 - 2. 96 2. 37 6. 05 - 3. 08 Try : sum of 6. 85 & 3. 91 difference of 3. 95 from 4. 82 6. 05 minus 3. 08 2. 97

REVIEW # 2 MATH 8

MULTIPLICATION There are three common ways of writing “ 5 times 3”: 1) Multiplying as repeated addition Example: Multiply 42 x 3 This is equivalent to 42 + 42 = 126 5 x 3 , 5 ● 3 , and (5)(3) 2) Multiplying by thinking about area Example: Multiply 5 ● 3 We can think of this as 3 groups of 5 objects or 5 groups of 3 objects: This is also why we multiply to find the area of rectangle. 5 ● 3 = 15 3) Multiplying using place values 5●(20+3) = 5 ● 20 + 5 ● 3 The idea that is called the distributive property. Example: Multiply 28 ● 6 We can write this as 28 ● 6 = (20+8) ● 6 Then (20+8) ● 6 = 20 ● 6 + 8 ● 6 = 120 + 48 = 168 Example: Multiply 28 ● 34 This can be thought of as areas, as pictured to the left Then 20 ● 30 + 20 ● 4 + 8 ● 30 + 8 ● 4 = 600 + 80 + 240 + 32 = 952

MULTIPLICATION 4 Ex 2 381 x 15 Ex 1 + 1 593 19 0 5 38 1 0 5715 x 2 11 8 6 Try 2 1 875 x 3 2625 Try 124 x 36 + 744 3720 4464 Put a zero when you start the second line

LONG DIVISION 17 - • 5 35 -35 0 this means no remainder