Y7 Mental Arithmetic
Across
- 4. This is the result you get when you divide one number by another. For example, the quotient of 8 ÷ 2 is 4.
- 5. This tells you how many times to multiply a number by itself. For example, in 2^3, 3 is the power, meaning 2 is multiplied by itself 3 times.
- 9. This means adjusting a number to be closer to a round number or to a specific place value. For example, rounding 67 to the nearest ten gives you 70.
- 12. This means you can swap numbers around when adding or multiplying and still get the same answer. For example, 4 + 5 is the same as 5 + 4.
- 14. This is just the plural of index. It means more than one index or exponent.
- 15. This is a set of rules that tells you which calculations to do first in a math problem. A common way to remember this is PEMDAS (Parentheses, Exponents, Multiplication and Division, Addition and Subtraction).
- 16. These are numbers that you can get by multiplying a whole number by itself three times. For example, 8 is a perfect cube because 2 x 2 x 2 = 8.
- 18. In math, the base is the number that gets multiplied when using exponents. For example, in 3^4, 3 is the base and it means 3 is multiplied by itself 4 times.
- 19. This is the number you are dividing up. For example, in 15 ÷ 3, 15 is the dividend.
- 21. This means making a smart guess about a number or result. It's like rounding to a simpler number to make math easier.
- 22. Form: This shows a number as the sum of its parts. For example, 345 in expanded form is 300 + 40 + 5.
Down
- 1. This is the number you are dividing by. In 15 ÷ 3, 3 is the divisor.
- 2. This rule lets you multiply a number by a group of numbers added together. For example, 2 x (3 + 4) is the same as (2 x 3) + (2 x 4).
- 3. In math, this is another way to talk about the power or exponent. It tells you how many times to multiply the base by itself.
- 6. This is a fancy way of saying that it doesn't matter how you group numbers when you're adding or multiplying them. For example, (2 + 3) + 4 is the same as 2 + (3 + 4).
- 7. This is a number that, when multiplied by itself, gives you the original number. For example, the square root of 25 is 5, because 5 x 5 = 25.
- 8. This is a number that, when multiplied by itself three times, gives you the original number. For example, the cube root of 27 is 3, because 3 x 3 x 3 = 27.
- 10. These are numbers that you can get by multiplying a whole number by itself. For example, 16 is a perfect square because 4 x 4 = 16.
- 11. This is what is left over after dividing. For example, in 10 ÷ 3, 1 is the remainder because 3 goes into 10 three times, with 1 left over.
- 13. This is the answer you get when you multiply numbers together. For example, the product of 3 and 4 is 12.
- 17. Conventions: These are the agreed-upon rules and ways we do math, like always doing multiplication before addition.
- 20. This is a way of writing numbers using bases and exponents. For example, 2^3 is the index form, showing 2 is the base and 3 is the index.