\( \begin{array}{lll}\text { d) } 176+239 & \text { h) } 284-179 & \text { 1) } 6248-4550 \\ \text { a) } 687-190 & \text { b) } 145 \times 80 & \text { c) } 800 \times 300 \\ \text { Multiply or divide the following without using a calculator. Check your answers using estimation: } \\ \begin{array}{lll}\text { a) } 65 \times 7 & \text { e) } 423 \div 9 & \text { f) } 184 \times 6 \\ \text { d) } 73 \times 8 & \text { b) } 159 \div 3 & \text { (i) } 984 \div 4 \\ \text { c9 } 720-6 & & \text { c) } 3129+4207-1125\end{array}\end{array} \)

When you dive into multiplication and division, it's like stepping into the world of magic numbers! For instance, when doing \( 65 \times 7 \), you can think of it as seven groups of 60 and seven groups of 5. That's 420 plus 35, which gives you 455! A great estimation tactic is to round to the nearest ten; in this case, 60 becomes easy to work with! Don’t forget to assure your calculations with some quick estimates! For \( 423 \div 9 \), round \( 423 \) to \( 420 \), which is close to \( 450 \), making the division a bit easier! Yes, it sounds like a brain teaser, but ultimately any number in the love world of math can be approached in a fun way! It helps build confidence in your numerical skills, turning what seems daunting into a playful challenge!